2020-04-27 20:08:36

by Christoph Hellwig

[permalink] [raw]
Subject: remove set_fs calls from the coredump code v4

Hi all,

this series gets rid of playing with the address limit in the exec and
coredump code. Most of this was fairly trivial, the biggest changes are
those to the spufs coredump code.

Changes since v3:
- fix x86 compilation with x32 in the new version of the signal code
- split the exec patches into a new series

Changes since v2:
- don't cleanup the compat siginfo calling conventions, use the patch
variant from Eric with slight coding style fixes instead.

Changes since v1:
- properly spell NUL
- properly handle the compat siginfo case in ELF coredumps


2020-04-27 20:08:40

by Christoph Hellwig

[permalink] [raw]
Subject: [PATCH 1/5] powerpc/spufs: simplify spufs core dumping

Replace the coredump ->read method with a ->dump method that must call
dump_emit itself. That way we avoid a buffer allocation an messing with
set_fs() to call into code that is intended to deal with user buffers.
For the ->get case we can now use a small on-stack buffer and avoid
memory allocations as well.

Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Arnd Bergmann <[email protected]>
Reviewed-by: Jeremy Kerr <[email protected]>
---
arch/powerpc/platforms/cell/spufs/coredump.c | 87 ++----
arch/powerpc/platforms/cell/spufs/file.c | 273 ++++++++++---------
arch/powerpc/platforms/cell/spufs/spufs.h | 3 +-
3 files changed, 170 insertions(+), 193 deletions(-)

diff --git a/arch/powerpc/platforms/cell/spufs/coredump.c b/arch/powerpc/platforms/cell/spufs/coredump.c
index 8b3296b62f651..3b75e8f60609c 100644
--- a/arch/powerpc/platforms/cell/spufs/coredump.c
+++ b/arch/powerpc/platforms/cell/spufs/coredump.c
@@ -21,22 +21,6 @@

#include "spufs.h"

-static ssize_t do_coredump_read(int num, struct spu_context *ctx, void *buffer,
- size_t size, loff_t *off)
-{
- u64 data;
- int ret;
-
- if (spufs_coredump_read[num].read)
- return spufs_coredump_read[num].read(ctx, buffer, size, off);
-
- data = spufs_coredump_read[num].get(ctx);
- ret = snprintf(buffer, size, "0x%.16llx", data);
- if (ret >= size)
- return size;
- return ++ret; /* count trailing NULL */
-}
-
static int spufs_ctx_note_size(struct spu_context *ctx, int dfd)
{
int i, sz, total = 0;
@@ -118,58 +102,43 @@ int spufs_coredump_extra_notes_size(void)
static int spufs_arch_write_note(struct spu_context *ctx, int i,
struct coredump_params *cprm, int dfd)
{
- loff_t pos = 0;
- int sz, rc, total = 0;
- const int bufsz = PAGE_SIZE;
- char *name;
- char fullname[80], *buf;
+ size_t sz = spufs_coredump_read[i].size;
+ char fullname[80];
struct elf_note en;
- size_t skip;
-
- buf = (void *)get_zeroed_page(GFP_KERNEL);
- if (!buf)
- return -ENOMEM;
+ size_t ret;

- name = spufs_coredump_read[i].name;
- sz = spufs_coredump_read[i].size;
-
- sprintf(fullname, "SPU/%d/%s", dfd, name);
+ sprintf(fullname, "SPU/%d/%s", dfd, spufs_coredump_read[i].name);
en.n_namesz = strlen(fullname) + 1;
en.n_descsz = sz;
en.n_type = NT_SPU;

if (!dump_emit(cprm, &en, sizeof(en)))
- goto Eio;
-
+ return -EIO;
if (!dump_emit(cprm, fullname, en.n_namesz))
- goto Eio;
-
+ return -EIO;
if (!dump_align(cprm, 4))
- goto Eio;
-
- do {
- rc = do_coredump_read(i, ctx, buf, bufsz, &pos);
- if (rc > 0) {
- if (!dump_emit(cprm, buf, rc))
- goto Eio;
- total += rc;
- }
- } while (rc == bufsz && total < sz);
-
- if (rc < 0)
- goto out;
-
- skip = roundup(cprm->pos - total + sz, 4) - cprm->pos;
- if (!dump_skip(cprm, skip))
- goto Eio;
-
- rc = 0;
-out:
- free_page((unsigned long)buf);
- return rc;
-Eio:
- free_page((unsigned long)buf);
- return -EIO;
+ return -EIO;
+
+ if (spufs_coredump_read[i].dump) {
+ ret = spufs_coredump_read[i].dump(ctx, cprm);
+ if (ret < 0)
+ return ret;
+ } else {
+ char buf[32];
+
+ ret = snprintf(buf, sizeof(buf), "0x%.16llx",
+ spufs_coredump_read[i].get(ctx));
+ if (ret >= sizeof(buf))
+ return sizeof(buf);
+
+ /* count trailing the NULL: */
+ if (!dump_emit(cprm, buf, ret + 1))
+ return -EIO;
+ }
+
+ if (!dump_skip(cprm, roundup(cprm->pos - ret + sz, 4) - cprm->pos))
+ return -EIO;
+ return 0;
}

int spufs_coredump_extra_notes_write(struct coredump_params *cprm)
diff --git a/arch/powerpc/platforms/cell/spufs/file.c b/arch/powerpc/platforms/cell/spufs/file.c
index c0f950a3f4e1f..0f8c3d692af0c 100644
--- a/arch/powerpc/platforms/cell/spufs/file.c
+++ b/arch/powerpc/platforms/cell/spufs/file.c
@@ -9,6 +9,7 @@

#undef DEBUG

+#include <linux/coredump.h>
#include <linux/fs.h>
#include <linux/ioctl.h>
#include <linux/export.h>
@@ -129,6 +130,14 @@ static ssize_t spufs_attr_write(struct file *file, const char __user *buf,
return ret;
}

+static ssize_t spufs_dump_emit(struct coredump_params *cprm, void *buf,
+ size_t size)
+{
+ if (!dump_emit(cprm, buf, size))
+ return -EIO;
+ return size;
+}
+
#define DEFINE_SPUFS_SIMPLE_ATTRIBUTE(__fops, __get, __set, __fmt) \
static int __fops ## _open(struct inode *inode, struct file *file) \
{ \
@@ -172,12 +181,9 @@ spufs_mem_release(struct inode *inode, struct file *file)
}

static ssize_t
-__spufs_mem_read(struct spu_context *ctx, char __user *buffer,
- size_t size, loff_t *pos)
+spufs_mem_dump(struct spu_context *ctx, struct coredump_params *cprm)
{
- char *local_store = ctx->ops->get_ls(ctx);
- return simple_read_from_buffer(buffer, size, pos, local_store,
- LS_SIZE);
+ return spufs_dump_emit(cprm, ctx->ops->get_ls(ctx), LS_SIZE);
}

static ssize_t
@@ -190,7 +196,8 @@ spufs_mem_read(struct file *file, char __user *buffer,
ret = spu_acquire(ctx);
if (ret)
return ret;
- ret = __spufs_mem_read(ctx, buffer, size, pos);
+ ret = simple_read_from_buffer(buffer, size, pos, ctx->ops->get_ls(ctx),
+ LS_SIZE);
spu_release(ctx);

return ret;
@@ -459,12 +466,10 @@ spufs_regs_open(struct inode *inode, struct file *file)
}

static ssize_t
-__spufs_regs_read(struct spu_context *ctx, char __user *buffer,
- size_t size, loff_t *pos)
+spufs_regs_dump(struct spu_context *ctx, struct coredump_params *cprm)
{
- struct spu_lscsa *lscsa = ctx->csa.lscsa;
- return simple_read_from_buffer(buffer, size, pos,
- lscsa->gprs, sizeof lscsa->gprs);
+ return spufs_dump_emit(cprm, ctx->csa.lscsa->gprs,
+ sizeof(ctx->csa.lscsa->gprs));
}

static ssize_t
@@ -482,7 +487,8 @@ spufs_regs_read(struct file *file, char __user *buffer,
ret = spu_acquire_saved(ctx);
if (ret)
return ret;
- ret = __spufs_regs_read(ctx, buffer, size, pos);
+ ret = simple_read_from_buffer(buffer, size, pos, ctx->csa.lscsa->gprs,
+ sizeof(ctx->csa.lscsa->gprs));
spu_release_saved(ctx);
return ret;
}
@@ -517,12 +523,10 @@ static const struct file_operations spufs_regs_fops = {
};

static ssize_t
-__spufs_fpcr_read(struct spu_context *ctx, char __user * buffer,
- size_t size, loff_t * pos)
+spufs_fpcr_dump(struct spu_context *ctx, struct coredump_params *cprm)
{
- struct spu_lscsa *lscsa = ctx->csa.lscsa;
- return simple_read_from_buffer(buffer, size, pos,
- &lscsa->fpcr, sizeof(lscsa->fpcr));
+ return spufs_dump_emit(cprm, &ctx->csa.lscsa->fpcr,
+ sizeof(ctx->csa.lscsa->fpcr));
}

static ssize_t
@@ -535,7 +539,8 @@ spufs_fpcr_read(struct file *file, char __user * buffer,
ret = spu_acquire_saved(ctx);
if (ret)
return ret;
- ret = __spufs_fpcr_read(ctx, buffer, size, pos);
+ ret = simple_read_from_buffer(buffer, size, pos, &ctx->csa.lscsa->fpcr,
+ sizeof(ctx->csa.lscsa->fpcr));
spu_release_saved(ctx);
return ret;
}
@@ -967,28 +972,26 @@ spufs_signal1_release(struct inode *inode, struct file *file)
return 0;
}

-static ssize_t __spufs_signal1_read(struct spu_context *ctx, char __user *buf,
- size_t len, loff_t *pos)
+static ssize_t spufs_signal1_dump(struct spu_context *ctx,
+ struct coredump_params *cprm)
{
- int ret = 0;
- u32 data;
+ if (!ctx->csa.spu_chnlcnt_RW[3])
+ return 0;
+ return spufs_dump_emit(cprm, &ctx->csa.spu_chnldata_RW[3],
+ sizeof(ctx->csa.spu_chnldata_RW[3]));
+}

- if (len < 4)
+static ssize_t __spufs_signal1_read(struct spu_context *ctx, char __user *buf,
+ size_t len)
+{
+ if (len < sizeof(ctx->csa.spu_chnldata_RW[3]))
return -EINVAL;
-
- if (ctx->csa.spu_chnlcnt_RW[3]) {
- data = ctx->csa.spu_chnldata_RW[3];
- ret = 4;
- }
-
- if (!ret)
- goto out;
-
- if (copy_to_user(buf, &data, 4))
+ if (!ctx->csa.spu_chnlcnt_RW[3])
+ return 0;
+ if (copy_to_user(buf, &ctx->csa.spu_chnldata_RW[3],
+ sizeof(ctx->csa.spu_chnldata_RW[3])))
return -EFAULT;
-
-out:
- return ret;
+ return sizeof(ctx->csa.spu_chnldata_RW[3]);
}

static ssize_t spufs_signal1_read(struct file *file, char __user *buf,
@@ -1000,7 +1003,7 @@ static ssize_t spufs_signal1_read(struct file *file, char __user *buf,
ret = spu_acquire_saved(ctx);
if (ret)
return ret;
- ret = __spufs_signal1_read(ctx, buf, len, pos);
+ ret = __spufs_signal1_read(ctx, buf, len);
spu_release_saved(ctx);

return ret;
@@ -1104,28 +1107,26 @@ spufs_signal2_release(struct inode *inode, struct file *file)
return 0;
}

-static ssize_t __spufs_signal2_read(struct spu_context *ctx, char __user *buf,
- size_t len, loff_t *pos)
+static ssize_t spufs_signal2_dump(struct spu_context *ctx,
+ struct coredump_params *cprm)
{
- int ret = 0;
- u32 data;
+ if (!ctx->csa.spu_chnlcnt_RW[4])
+ return 0;
+ return spufs_dump_emit(cprm, &ctx->csa.spu_chnldata_RW[4],
+ sizeof(ctx->csa.spu_chnldata_RW[4]));
+}

- if (len < 4)
+static ssize_t __spufs_signal2_read(struct spu_context *ctx, char __user *buf,
+ size_t len)
+{
+ if (len < sizeof(ctx->csa.spu_chnldata_RW[4]))
return -EINVAL;
-
- if (ctx->csa.spu_chnlcnt_RW[4]) {
- data = ctx->csa.spu_chnldata_RW[4];
- ret = 4;
- }
-
- if (!ret)
- goto out;
-
- if (copy_to_user(buf, &data, 4))
+ if (!ctx->csa.spu_chnlcnt_RW[4])
+ return 0;
+ if (copy_to_user(buf, &ctx->csa.spu_chnldata_RW[4],
+ sizeof(ctx->csa.spu_chnldata_RW[4])))
return -EFAULT;
-
-out:
- return ret;
+ return sizeof(ctx->csa.spu_chnldata_RW[4]);
}

static ssize_t spufs_signal2_read(struct file *file, char __user *buf,
@@ -1137,7 +1138,7 @@ static ssize_t spufs_signal2_read(struct file *file, char __user *buf,
ret = spu_acquire_saved(ctx);
if (ret)
return ret;
- ret = __spufs_signal2_read(ctx, buf, len, pos);
+ ret = __spufs_signal2_read(ctx, buf, len);
spu_release_saved(ctx);

return ret;
@@ -1961,18 +1962,13 @@ static const struct file_operations spufs_caps_fops = {
.release = single_release,
};

-static ssize_t __spufs_mbox_info_read(struct spu_context *ctx,
- char __user *buf, size_t len, loff_t *pos)
+static ssize_t spufs_mbox_info_dump(struct spu_context *ctx,
+ struct coredump_params *cprm)
{
- u32 data;
-
- /* EOF if there's no entry in the mbox */
if (!(ctx->csa.prob.mb_stat_R & 0x0000ff))
return 0;
-
- data = ctx->csa.prob.pu_mb_R;
-
- return simple_read_from_buffer(buf, len, pos, &data, sizeof data);
+ return spufs_dump_emit(cprm, &ctx->csa.prob.pu_mb_R,
+ sizeof(ctx->csa.prob.pu_mb_R));
}

static ssize_t spufs_mbox_info_read(struct file *file, char __user *buf,
@@ -1988,7 +1984,12 @@ static ssize_t spufs_mbox_info_read(struct file *file, char __user *buf,
if (ret)
return ret;
spin_lock(&ctx->csa.register_lock);
- ret = __spufs_mbox_info_read(ctx, buf, len, pos);
+ /* EOF if there's no entry in the mbox */
+ if (ctx->csa.prob.mb_stat_R & 0x0000ff) {
+ ret = simple_read_from_buffer(buf, len, pos,
+ &ctx->csa.prob.pu_mb_R,
+ sizeof(ctx->csa.prob.pu_mb_R));
+ }
spin_unlock(&ctx->csa.register_lock);
spu_release_saved(ctx);

@@ -2001,18 +2002,13 @@ static const struct file_operations spufs_mbox_info_fops = {
.llseek = generic_file_llseek,
};

-static ssize_t __spufs_ibox_info_read(struct spu_context *ctx,
- char __user *buf, size_t len, loff_t *pos)
+static ssize_t spufs_ibox_info_dump(struct spu_context *ctx,
+ struct coredump_params *cprm)
{
- u32 data;
-
- /* EOF if there's no entry in the ibox */
if (!(ctx->csa.prob.mb_stat_R & 0xff0000))
return 0;
-
- data = ctx->csa.priv2.puint_mb_R;
-
- return simple_read_from_buffer(buf, len, pos, &data, sizeof data);
+ return spufs_dump_emit(cprm, &ctx->csa.priv2.puint_mb_R,
+ sizeof(ctx->csa.priv2.puint_mb_R));
}

static ssize_t spufs_ibox_info_read(struct file *file, char __user *buf,
@@ -2028,7 +2024,12 @@ static ssize_t spufs_ibox_info_read(struct file *file, char __user *buf,
if (ret)
return ret;
spin_lock(&ctx->csa.register_lock);
- ret = __spufs_ibox_info_read(ctx, buf, len, pos);
+ /* EOF if there's no entry in the ibox */
+ if (ctx->csa.prob.mb_stat_R & 0xff0000) {
+ ret = simple_read_from_buffer(buf, len, pos,
+ &ctx->csa.priv2.puint_mb_R,
+ sizeof(ctx->csa.priv2.puint_mb_R));
+ }
spin_unlock(&ctx->csa.register_lock);
spu_release_saved(ctx);

@@ -2041,21 +2042,16 @@ static const struct file_operations spufs_ibox_info_fops = {
.llseek = generic_file_llseek,
};

-static ssize_t __spufs_wbox_info_read(struct spu_context *ctx,
- char __user *buf, size_t len, loff_t *pos)
+static size_t spufs_wbox_info_cnt(struct spu_context *ctx)
{
- int i, cnt;
- u32 data[4];
- u32 wbox_stat;
-
- wbox_stat = ctx->csa.prob.mb_stat_R;
- cnt = 4 - ((wbox_stat & 0x00ff00) >> 8);
- for (i = 0; i < cnt; i++) {
- data[i] = ctx->csa.spu_mailbox_data[i];
- }
+ return (4 - ((ctx->csa.prob.mb_stat_R & 0x00ff00) >> 8)) * sizeof(u32);
+}

- return simple_read_from_buffer(buf, len, pos, &data,
- cnt * sizeof(u32));
+static ssize_t spufs_wbox_info_dump(struct spu_context *ctx,
+ struct coredump_params *cprm)
+{
+ return spufs_dump_emit(cprm, &ctx->csa.spu_mailbox_data,
+ spufs_wbox_info_cnt(ctx));
}

static ssize_t spufs_wbox_info_read(struct file *file, char __user *buf,
@@ -2071,7 +2067,8 @@ static ssize_t spufs_wbox_info_read(struct file *file, char __user *buf,
if (ret)
return ret;
spin_lock(&ctx->csa.register_lock);
- ret = __spufs_wbox_info_read(ctx, buf, len, pos);
+ ret = simple_read_from_buffer(buf, len, pos, &ctx->csa.spu_mailbox_data,
+ spufs_wbox_info_cnt(ctx));
spin_unlock(&ctx->csa.register_lock);
spu_release_saved(ctx);

@@ -2084,36 +2081,42 @@ static const struct file_operations spufs_wbox_info_fops = {
.llseek = generic_file_llseek,
};

-static ssize_t __spufs_dma_info_read(struct spu_context *ctx,
- char __user *buf, size_t len, loff_t *pos)
+static void __spufs_dma_info_read(struct spu_context *ctx,
+ struct spu_dma_info *info)
{
- struct spu_dma_info info;
- struct mfc_cq_sr *qp, *spuqp;
int i;

- info.dma_info_type = ctx->csa.priv2.spu_tag_status_query_RW;
- info.dma_info_mask = ctx->csa.lscsa->tag_mask.slot[0];
- info.dma_info_status = ctx->csa.spu_chnldata_RW[24];
- info.dma_info_stall_and_notify = ctx->csa.spu_chnldata_RW[25];
- info.dma_info_atomic_command_status = ctx->csa.spu_chnldata_RW[27];
+ info->dma_info_type = ctx->csa.priv2.spu_tag_status_query_RW;
+ info->dma_info_mask = ctx->csa.lscsa->tag_mask.slot[0];
+ info->dma_info_status = ctx->csa.spu_chnldata_RW[24];
+ info->dma_info_stall_and_notify = ctx->csa.spu_chnldata_RW[25];
+ info->dma_info_atomic_command_status = ctx->csa.spu_chnldata_RW[27];
+
for (i = 0; i < 16; i++) {
- qp = &info.dma_info_command_data[i];
- spuqp = &ctx->csa.priv2.spuq[i];
+ struct mfc_cq_sr *qp = &info->dma_info_command_data[i];
+ struct mfc_cq_sr *spuqp = &ctx->csa.priv2.spuq[i];

qp->mfc_cq_data0_RW = spuqp->mfc_cq_data0_RW;
qp->mfc_cq_data1_RW = spuqp->mfc_cq_data1_RW;
qp->mfc_cq_data2_RW = spuqp->mfc_cq_data2_RW;
qp->mfc_cq_data3_RW = spuqp->mfc_cq_data3_RW;
}
+}
+
+static ssize_t spufs_dma_info_dump(struct spu_context *ctx,
+ struct coredump_params *cprm)
+{
+ struct spu_dma_info info;

- return simple_read_from_buffer(buf, len, pos, &info,
- sizeof info);
+ __spufs_dma_info_read(ctx, &info);
+ return spufs_dump_emit(cprm, &info, sizeof(info));
}

static ssize_t spufs_dma_info_read(struct file *file, char __user *buf,
size_t len, loff_t *pos)
{
struct spu_context *ctx = file->private_data;
+ struct spu_dma_info info;
int ret;

if (!access_ok(buf, len))
@@ -2123,7 +2126,8 @@ static ssize_t spufs_dma_info_read(struct file *file, char __user *buf,
if (ret)
return ret;
spin_lock(&ctx->csa.register_lock);
- ret = __spufs_dma_info_read(ctx, buf, len, pos);
+ __spufs_dma_info_read(ctx, &info);
+ ret = simple_read_from_buffer(buf, len, pos, &info, sizeof(info));
spin_unlock(&ctx->csa.register_lock);
spu_release_saved(ctx);

@@ -2136,48 +2140,53 @@ static const struct file_operations spufs_dma_info_fops = {
.llseek = no_llseek,
};

-static ssize_t __spufs_proxydma_info_read(struct spu_context *ctx,
- char __user *buf, size_t len, loff_t *pos)
+static void __spufs_proxydma_info_read(struct spu_context *ctx,
+ struct spu_proxydma_info *info)
{
- struct spu_proxydma_info info;
- struct mfc_cq_sr *qp, *puqp;
- int ret = sizeof info;
int i;

- if (len < ret)
- return -EINVAL;
-
- if (!access_ok(buf, len))
- return -EFAULT;
+ info->proxydma_info_type = ctx->csa.prob.dma_querytype_RW;
+ info->proxydma_info_mask = ctx->csa.prob.dma_querymask_RW;
+ info->proxydma_info_status = ctx->csa.prob.dma_tagstatus_R;

- info.proxydma_info_type = ctx->csa.prob.dma_querytype_RW;
- info.proxydma_info_mask = ctx->csa.prob.dma_querymask_RW;
- info.proxydma_info_status = ctx->csa.prob.dma_tagstatus_R;
for (i = 0; i < 8; i++) {
- qp = &info.proxydma_info_command_data[i];
- puqp = &ctx->csa.priv2.puq[i];
+ struct mfc_cq_sr *qp = &info->proxydma_info_command_data[i];
+ struct mfc_cq_sr *puqp = &ctx->csa.priv2.puq[i];

qp->mfc_cq_data0_RW = puqp->mfc_cq_data0_RW;
qp->mfc_cq_data1_RW = puqp->mfc_cq_data1_RW;
qp->mfc_cq_data2_RW = puqp->mfc_cq_data2_RW;
qp->mfc_cq_data3_RW = puqp->mfc_cq_data3_RW;
}
+}
+
+static ssize_t spufs_proxydma_info_dump(struct spu_context *ctx,
+ struct coredump_params *cprm)
+{
+ struct spu_proxydma_info info;

- return simple_read_from_buffer(buf, len, pos, &info,
- sizeof info);
+ __spufs_proxydma_info_read(ctx, &info);
+ return spufs_dump_emit(cprm, &info, sizeof(info));
}

static ssize_t spufs_proxydma_info_read(struct file *file, char __user *buf,
size_t len, loff_t *pos)
{
struct spu_context *ctx = file->private_data;
+ struct spu_proxydma_info info;
int ret;

+ if (len < sizeof(info))
+ return -EINVAL;
+ if (!access_ok(buf, len))
+ return -EFAULT;
+
ret = spu_acquire_saved(ctx);
if (ret)
return ret;
spin_lock(&ctx->csa.register_lock);
- ret = __spufs_proxydma_info_read(ctx, buf, len, pos);
+ __spufs_proxydma_info_read(ctx, &info);
+ ret = simple_read_from_buffer(buf, len, pos, &info, sizeof(info));
spin_unlock(&ctx->csa.register_lock);
spu_release_saved(ctx);

@@ -2625,23 +2634,23 @@ const struct spufs_tree_descr spufs_dir_debug_contents[] = {
};

const struct spufs_coredump_reader spufs_coredump_read[] = {
- { "regs", __spufs_regs_read, NULL, sizeof(struct spu_reg128[128])},
- { "fpcr", __spufs_fpcr_read, NULL, sizeof(struct spu_reg128) },
+ { "regs", spufs_regs_dump, NULL, sizeof(struct spu_reg128[128])},
+ { "fpcr", spufs_fpcr_dump, NULL, sizeof(struct spu_reg128) },
{ "lslr", NULL, spufs_lslr_get, 19 },
{ "decr", NULL, spufs_decr_get, 19 },
{ "decr_status", NULL, spufs_decr_status_get, 19 },
- { "mem", __spufs_mem_read, NULL, LS_SIZE, },
- { "signal1", __spufs_signal1_read, NULL, sizeof(u32) },
+ { "mem", spufs_mem_dump, NULL, LS_SIZE, },
+ { "signal1", spufs_signal1_dump, NULL, sizeof(u32) },
{ "signal1_type", NULL, spufs_signal1_type_get, 19 },
- { "signal2", __spufs_signal2_read, NULL, sizeof(u32) },
+ { "signal2", spufs_signal2_dump, NULL, sizeof(u32) },
{ "signal2_type", NULL, spufs_signal2_type_get, 19 },
{ "event_mask", NULL, spufs_event_mask_get, 19 },
{ "event_status", NULL, spufs_event_status_get, 19 },
- { "mbox_info", __spufs_mbox_info_read, NULL, sizeof(u32) },
- { "ibox_info", __spufs_ibox_info_read, NULL, sizeof(u32) },
- { "wbox_info", __spufs_wbox_info_read, NULL, 4 * sizeof(u32)},
- { "dma_info", __spufs_dma_info_read, NULL, sizeof(struct spu_dma_info)},
- { "proxydma_info", __spufs_proxydma_info_read,
+ { "mbox_info", spufs_mbox_info_dump, NULL, sizeof(u32) },
+ { "ibox_info", spufs_ibox_info_dump, NULL, sizeof(u32) },
+ { "wbox_info", spufs_wbox_info_dump, NULL, 4 * sizeof(u32)},
+ { "dma_info", spufs_dma_info_dump, NULL, sizeof(struct spu_dma_info)},
+ { "proxydma_info", spufs_proxydma_info_dump,
NULL, sizeof(struct spu_proxydma_info)},
{ "object-id", NULL, spufs_object_id_get, 19 },
{ "npc", NULL, spufs_npc_get, 19 },
diff --git a/arch/powerpc/platforms/cell/spufs/spufs.h b/arch/powerpc/platforms/cell/spufs/spufs.h
index 413c89afe1126..1ba4d884febfa 100644
--- a/arch/powerpc/platforms/cell/spufs/spufs.h
+++ b/arch/powerpc/platforms/cell/spufs/spufs.h
@@ -337,8 +337,7 @@ void spufs_dma_callback(struct spu *spu, int type);
extern struct spu_coredump_calls spufs_coredump_calls;
struct spufs_coredump_reader {
char *name;
- ssize_t (*read)(struct spu_context *ctx,
- char __user *buffer, size_t size, loff_t *pos);
+ ssize_t (*dump)(struct spu_context *ctx, struct coredump_params *cprm);
u64 (*get)(struct spu_context *ctx);
size_t size;
};
--
2.26.1

2020-04-27 20:08:47

by Christoph Hellwig

[permalink] [raw]
Subject: [PATCH 2/5] signal: factor copy_siginfo_to_external32 from copy_siginfo_to_user32

From: "Eric W. Biederman" <[email protected]>

To remove the use of set_fs in the coredump code there needs to be a
way to convert a kernel siginfo to a userspace compat siginfo.

Call that function copy_siginfo_to_compat and factor it out of
copy_siginfo_to_user32.

The existence of x32 complicates this code. On x32 SIGCHLD uses 64bit
times for utime and stime. As only SIGCHLD is affected and SIGCHLD
never causes a coredump I have avoided handling that case.

Signed-off-by: "Eric W. Biederman" <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
---
include/linux/compat.h | 2 +
kernel/signal.c | 113 ++++++++++++++++++++++-------------------
2 files changed, 62 insertions(+), 53 deletions(-)

diff --git a/include/linux/compat.h b/include/linux/compat.h
index 0480ba4db5929..adbfe8f688d92 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -402,6 +402,8 @@ long compat_get_bitmap(unsigned long *mask, const compat_ulong_t __user *umask,
unsigned long bitmap_size);
long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask,
unsigned long bitmap_size);
+void copy_siginfo_to_external32(struct compat_siginfo *to,
+ const struct kernel_siginfo *from);
int copy_siginfo_from_user32(kernel_siginfo_t *to, const struct compat_siginfo __user *from);
int copy_siginfo_to_user32(struct compat_siginfo __user *to, const kernel_siginfo_t *from);
int get_compat_sigevent(struct sigevent *event,
diff --git a/kernel/signal.c b/kernel/signal.c
index 284fc1600063b..244c69c4261e0 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3235,94 +3235,101 @@ int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
}

#ifdef CONFIG_COMPAT
-int copy_siginfo_to_user32(struct compat_siginfo __user *to,
- const struct kernel_siginfo *from)
-#if defined(CONFIG_X86_X32_ABI) || defined(CONFIG_IA32_EMULATION)
+void copy_siginfo_to_external32(struct compat_siginfo *to,
+ const struct kernel_siginfo *from)
{
- return __copy_siginfo_to_user32(to, from, in_x32_syscall());
-}
-int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
- const struct kernel_siginfo *from, bool x32_ABI)
-#endif
-{
- struct compat_siginfo new;
- memset(&new, 0, sizeof(new));
+ /*
+ * This function does not work properly for SIGCHLD on x32,
+ * but it does not need to as SIGCHLD never causes a coredump.
+ */
+ memset(to, 0, sizeof(*to));

- new.si_signo = from->si_signo;
- new.si_errno = from->si_errno;
- new.si_code = from->si_code;
+ to->si_signo = from->si_signo;
+ to->si_errno = from->si_errno;
+ to->si_code = from->si_code;
switch(siginfo_layout(from->si_signo, from->si_code)) {
case SIL_KILL:
- new.si_pid = from->si_pid;
- new.si_uid = from->si_uid;
+ to->si_pid = from->si_pid;
+ to->si_uid = from->si_uid;
break;
case SIL_TIMER:
- new.si_tid = from->si_tid;
- new.si_overrun = from->si_overrun;
- new.si_int = from->si_int;
+ to->si_tid = from->si_tid;
+ to->si_overrun = from->si_overrun;
+ to->si_int = from->si_int;
break;
case SIL_POLL:
- new.si_band = from->si_band;
- new.si_fd = from->si_fd;
+ to->si_band = from->si_band;
+ to->si_fd = from->si_fd;
break;
case SIL_FAULT:
- new.si_addr = ptr_to_compat(from->si_addr);
+ to->si_addr = ptr_to_compat(from->si_addr);
#ifdef __ARCH_SI_TRAPNO
- new.si_trapno = from->si_trapno;
+ to->si_trapno = from->si_trapno;
#endif
break;
case SIL_FAULT_MCEERR:
- new.si_addr = ptr_to_compat(from->si_addr);
+ to->si_addr = ptr_to_compat(from->si_addr);
#ifdef __ARCH_SI_TRAPNO
- new.si_trapno = from->si_trapno;
+ to->si_trapno = from->si_trapno;
#endif
- new.si_addr_lsb = from->si_addr_lsb;
+ to->si_addr_lsb = from->si_addr_lsb;
break;
case SIL_FAULT_BNDERR:
- new.si_addr = ptr_to_compat(from->si_addr);
+ to->si_addr = ptr_to_compat(from->si_addr);
#ifdef __ARCH_SI_TRAPNO
- new.si_trapno = from->si_trapno;
+ to->si_trapno = from->si_trapno;
#endif
- new.si_lower = ptr_to_compat(from->si_lower);
- new.si_upper = ptr_to_compat(from->si_upper);
+ to->si_lower = ptr_to_compat(from->si_lower);
+ to->si_upper = ptr_to_compat(from->si_upper);
break;
case SIL_FAULT_PKUERR:
- new.si_addr = ptr_to_compat(from->si_addr);
+ to->si_addr = ptr_to_compat(from->si_addr);
#ifdef __ARCH_SI_TRAPNO
- new.si_trapno = from->si_trapno;
+ to->si_trapno = from->si_trapno;
#endif
- new.si_pkey = from->si_pkey;
+ to->si_pkey = from->si_pkey;
break;
case SIL_CHLD:
- new.si_pid = from->si_pid;
- new.si_uid = from->si_uid;
- new.si_status = from->si_status;
-#ifdef CONFIG_X86_X32_ABI
- if (x32_ABI) {
- new._sifields._sigchld_x32._utime = from->si_utime;
- new._sifields._sigchld_x32._stime = from->si_stime;
- } else
-#endif
- {
- new.si_utime = from->si_utime;
- new.si_stime = from->si_stime;
- }
+ to->si_pid = from->si_pid;
+ to->si_uid = from->si_uid;
+ to->si_status = from->si_status;
+ to->si_utime = from->si_utime;
+ to->si_stime = from->si_stime;
break;
case SIL_RT:
- new.si_pid = from->si_pid;
- new.si_uid = from->si_uid;
- new.si_int = from->si_int;
+ to->si_pid = from->si_pid;
+ to->si_uid = from->si_uid;
+ to->si_int = from->si_int;
break;
case SIL_SYS:
- new.si_call_addr = ptr_to_compat(from->si_call_addr);
- new.si_syscall = from->si_syscall;
- new.si_arch = from->si_arch;
+ to->si_call_addr = ptr_to_compat(from->si_call_addr);
+ to->si_syscall = from->si_syscall;
+ to->si_arch = from->si_arch;
break;
}
+}

+int copy_siginfo_to_user32(struct compat_siginfo __user *to,
+ const struct kernel_siginfo *from)
+#if defined(CONFIG_X86_X32_ABI) || defined(CONFIG_IA32_EMULATION)
+{
+ return __copy_siginfo_to_user32(to, from, in_x32_syscall());
+}
+int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
+ const struct kernel_siginfo *from, bool x32_ABI)
+#endif
+{
+ struct compat_siginfo new;
+
+ copy_siginfo_to_external32(&new, from);
+#ifdef CONFIG_X86_X32_ABI
+ if (x32_ABI && from->si_signo == SIGCHLD) {
+ new._sifields._sigchld_x32._utime = from->si_utime;
+ new._sifields._sigchld_x32._stime = from->si_stime;
+ }
+#endif
if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
return -EFAULT;
-
return 0;
}

--
2.26.1

2020-04-27 20:09:30

by Christoph Hellwig

[permalink] [raw]
Subject: [PATCH 3/5] binfmt_elf: remove the set_fs in fill_siginfo_note

From: "Eric W. Biederman" <[email protected]>

The code in binfmt_elf.c is differnt from the rest of the code that
processes siginfo, as it sends siginfo from a kernel buffer to a file
rather than from kernel memory to userspace buffers. To remove it's
use of set_fs the code needs some different siginfo helpers.

Add the helper copy_siginfo_to_external to copy from the kernel's
internal siginfo layout to a buffer in the siginfo layout that
userspace expects.

Modify fill_siginfo_note to use copy_siginfo_to_external instead of
set_fs and copy_siginfo_to_user.

Update compat_binfmt_elf.c to use the previously added
copy_siginfo_to_external32 to handle the compat case.

Signed-off-by: "Eric W. Biederman" <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
---
fs/binfmt_elf.c | 5 +----
fs/compat_binfmt_elf.c | 2 +-
include/linux/signal.h | 8 ++++++++
3 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 13f25e241ac46..a1f57e20c3cf2 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1556,10 +1556,7 @@ static void fill_auxv_note(struct memelfnote *note, struct mm_struct *mm)
static void fill_siginfo_note(struct memelfnote *note, user_siginfo_t *csigdata,
const kernel_siginfo_t *siginfo)
{
- mm_segment_t old_fs = get_fs();
- set_fs(KERNEL_DS);
- copy_siginfo_to_user((user_siginfo_t __user *) csigdata, siginfo);
- set_fs(old_fs);
+ copy_siginfo_to_external(csigdata, siginfo);
fill_note(note, "CORE", NT_SIGINFO, sizeof(*csigdata), csigdata);
}

diff --git a/fs/compat_binfmt_elf.c b/fs/compat_binfmt_elf.c
index aaad4ca1217ef..fa0e24e1b7267 100644
--- a/fs/compat_binfmt_elf.c
+++ b/fs/compat_binfmt_elf.c
@@ -39,7 +39,7 @@
*/
#define user_long_t compat_long_t
#define user_siginfo_t compat_siginfo_t
-#define copy_siginfo_to_user copy_siginfo_to_user32
+#define copy_siginfo_to_external copy_siginfo_to_external32

/*
* The machine-dependent core note format types are defined in elfcore-compat.h,
diff --git a/include/linux/signal.h b/include/linux/signal.h
index 05bacd2ab1350..6bb1a3f0258c2 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -24,6 +24,14 @@ static inline void clear_siginfo(kernel_siginfo_t *info)

#define SI_EXPANSION_SIZE (sizeof(struct siginfo) - sizeof(struct kernel_siginfo))

+static inline void copy_siginfo_to_external(siginfo_t *to,
+ const kernel_siginfo_t *from)
+{
+ memcpy(to, from, sizeof(*from));
+ memset(((char *)to) + sizeof(struct kernel_siginfo), 0,
+ SI_EXPANSION_SIZE);
+}
+
int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from);
int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from);

--
2.26.1

2020-04-27 20:10:47

by Christoph Hellwig

[permalink] [raw]
Subject: [PATCH 5/5] binfmt_elf_fdpic: remove the set_fs(KERNEL_DS) in elf_fdpic_core_dump

There is no logic in elf_fdpic_core_dump itself or in the various arch
helpers called from it which use uaccess routines on kernel pointers
except for the file writes thate are nicely encapsulated by using
__kernel_write in dump_emit.

Signed-off-by: Christoph Hellwig <[email protected]>
---
fs/binfmt_elf_fdpic.c | 31 ++++++++++++-------------------
1 file changed, 12 insertions(+), 19 deletions(-)

diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 240f666635437..c62c17a5c34a9 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -1549,7 +1549,6 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
{
#define NUM_NOTES 6
int has_dumped = 0;
- mm_segment_t fs;
int segs;
int i;
struct vm_area_struct *vma;
@@ -1678,9 +1677,6 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
"LINUX", ELF_CORE_XFPREG_TYPE, sizeof(*xfpu), xfpu);
#endif

- fs = get_fs();
- set_fs(KERNEL_DS);
-
offset += sizeof(*elf); /* Elf header */
offset += segs * sizeof(struct elf_phdr); /* Program headers */

@@ -1695,7 +1691,7 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)

phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL);
if (!phdr4note)
- goto end_coredump;
+ goto cleanup;

fill_elf_note_phdr(phdr4note, sz, offset);
offset += sz;
@@ -1711,17 +1707,17 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
if (e_phnum == PN_XNUM) {
shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL);
if (!shdr4extnum)
- goto end_coredump;
+ goto cleanup;
fill_extnum_info(elf, shdr4extnum, e_shoff, segs);
}

offset = dataoff;

if (!dump_emit(cprm, elf, sizeof(*elf)))
- goto end_coredump;
+ goto cleanup;

if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note)))
- goto end_coredump;
+ goto cleanup;

/* write program headers for segments dump */
for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
@@ -1745,16 +1741,16 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
phdr.p_align = ELF_EXEC_PAGESIZE;

if (!dump_emit(cprm, &phdr, sizeof(phdr)))
- goto end_coredump;
+ goto cleanup;
}

if (!elf_core_write_extra_phdrs(cprm, offset))
- goto end_coredump;
+ goto cleanup;

/* write out the notes section */
for (i = 0; i < numnote; i++)
if (!writenote(notes + i, cprm))
- goto end_coredump;
+ goto cleanup;

/* write out the thread status notes section */
list_for_each(t, &thread_list) {
@@ -1763,21 +1759,21 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)

for (i = 0; i < tmp->num_notes; i++)
if (!writenote(&tmp->notes[i], cprm))
- goto end_coredump;
+ goto cleanup;
}

if (!dump_skip(cprm, dataoff - cprm->pos))
- goto end_coredump;
+ goto cleanup;

if (!elf_fdpic_dump_segments(cprm))
- goto end_coredump;
+ goto cleanup;

if (!elf_core_write_extra_data(cprm))
- goto end_coredump;
+ goto cleanup;

if (e_phnum == PN_XNUM) {
if (!dump_emit(cprm, shdr4extnum, sizeof(*shdr4extnum)))
- goto end_coredump;
+ goto cleanup;
}

if (cprm->file->f_pos != offset) {
@@ -1787,9 +1783,6 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
cprm->file->f_pos, offset);
}

-end_coredump:
- set_fs(fs);
-
cleanup:
while (!list_empty(&thread_list)) {
struct list_head *tmp = thread_list.next;
--
2.26.1

2020-04-27 20:11:03

by Christoph Hellwig

[permalink] [raw]
Subject: [PATCH 4/5] binfmt_elf: remove the set_fs(KERNEL_DS) in elf_core_dump

There is no logic in elf_core_dump itself or in the various arch helpers
called from it which use uaccess routines on kernel pointers except for
the file writes thate are nicely encapsulated by using __kernel_write in
dump_emit.

Signed-off-by: Christoph Hellwig <[email protected]>
---
fs/binfmt_elf.c | 40 +++++++++++++---------------------------
1 file changed, 13 insertions(+), 27 deletions(-)

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index a1f57e20c3cf2..b29b84595b09f 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1355,7 +1355,6 @@ static unsigned long vma_dump_size(struct vm_area_struct *vma,
vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ)) {
u32 __user *header = (u32 __user *) vma->vm_start;
u32 word;
- mm_segment_t fs = get_fs();
/*
* Doing it this way gets the constant folded by GCC.
*/
@@ -1368,14 +1367,8 @@ static unsigned long vma_dump_size(struct vm_area_struct *vma,
magic.elfmag[EI_MAG1] = ELFMAG1;
magic.elfmag[EI_MAG2] = ELFMAG2;
magic.elfmag[EI_MAG3] = ELFMAG3;
- /*
- * Switch to the user "segment" for get_user(),
- * then put back what elf_core_dump() had in place.
- */
- set_fs(USER_DS);
if (unlikely(get_user(word, header)))
word = 0;
- set_fs(fs);
if (word == magic.cmp)
return PAGE_SIZE;
}
@@ -2183,7 +2176,6 @@ static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
static int elf_core_dump(struct coredump_params *cprm)
{
int has_dumped = 0;
- mm_segment_t fs;
int segs, i;
size_t vma_data_size = 0;
struct vm_area_struct *vma, *gate_vma;
@@ -2236,9 +2228,6 @@ static int elf_core_dump(struct coredump_params *cprm)

has_dumped = 1;

- fs = get_fs();
- set_fs(KERNEL_DS);
-
offset += sizeof(elf); /* Elf header */
offset += segs * sizeof(struct elf_phdr); /* Program headers */

@@ -2250,7 +2239,7 @@ static int elf_core_dump(struct coredump_params *cprm)

phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL);
if (!phdr4note)
- goto end_coredump;
+ goto cleanup;

fill_elf_note_phdr(phdr4note, sz, offset);
offset += sz;
@@ -2265,7 +2254,7 @@ static int elf_core_dump(struct coredump_params *cprm)
vma_filesz = kvmalloc(array_size(sizeof(*vma_filesz), (segs - 1)),
GFP_KERNEL);
if (!vma_filesz)
- goto end_coredump;
+ goto cleanup;

for (i = 0, vma = first_vma(current, gate_vma); vma != NULL;
vma = next_vma(vma, gate_vma)) {
@@ -2283,17 +2272,17 @@ static int elf_core_dump(struct coredump_params *cprm)
if (e_phnum == PN_XNUM) {
shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL);
if (!shdr4extnum)
- goto end_coredump;
+ goto cleanup;
fill_extnum_info(&elf, shdr4extnum, e_shoff, segs);
}

offset = dataoff;

if (!dump_emit(cprm, &elf, sizeof(elf)))
- goto end_coredump;
+ goto cleanup;

if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note)))
- goto end_coredump;
+ goto cleanup;

/* Write program headers for segments dump */
for (i = 0, vma = first_vma(current, gate_vma); vma != NULL;
@@ -2315,22 +2304,22 @@ static int elf_core_dump(struct coredump_params *cprm)
phdr.p_align = ELF_EXEC_PAGESIZE;

if (!dump_emit(cprm, &phdr, sizeof(phdr)))
- goto end_coredump;
+ goto cleanup;
}

if (!elf_core_write_extra_phdrs(cprm, offset))
- goto end_coredump;
+ goto cleanup;

/* write out the notes section */
if (!write_note_info(&info, cprm))
- goto end_coredump;
+ goto cleanup;

if (elf_coredump_extra_notes_write(cprm))
- goto end_coredump;
+ goto cleanup;

/* Align to page */
if (!dump_skip(cprm, dataoff - cprm->pos))
- goto end_coredump;
+ goto cleanup;

for (i = 0, vma = first_vma(current, gate_vma); vma != NULL;
vma = next_vma(vma, gate_vma)) {
@@ -2352,22 +2341,19 @@ static int elf_core_dump(struct coredump_params *cprm)
} else
stop = !dump_skip(cprm, PAGE_SIZE);
if (stop)
- goto end_coredump;
+ goto cleanup;
}
}
dump_truncate(cprm);

if (!elf_core_write_extra_data(cprm))
- goto end_coredump;
+ goto cleanup;

if (e_phnum == PN_XNUM) {
if (!dump_emit(cprm, shdr4extnum, sizeof(*shdr4extnum)))
- goto end_coredump;
+ goto cleanup;
}

-end_coredump:
- set_fs(fs);
-
cleanup:
free_note_info(&info);
kfree(shdr4extnum);
--
2.26.1

2020-04-27 20:52:12

by Al Viro

[permalink] [raw]
Subject: Re: [PATCH 1/5] powerpc/spufs: simplify spufs core dumping

On Mon, Apr 27, 2020 at 10:06:21PM +0200, Christoph Hellwig wrote:

> @@ -1988,7 +1984,12 @@ static ssize_t spufs_mbox_info_read(struct file *file, char __user *buf,
> if (ret)
> return ret;
> spin_lock(&ctx->csa.register_lock);
> - ret = __spufs_mbox_info_read(ctx, buf, len, pos);
> + /* EOF if there's no entry in the mbox */
> + if (ctx->csa.prob.mb_stat_R & 0x0000ff) {
> + ret = simple_read_from_buffer(buf, len, pos,
> + &ctx->csa.prob.pu_mb_R,
> + sizeof(ctx->csa.prob.pu_mb_R));
> + }
> spin_unlock(&ctx->csa.register_lock);
> spu_release_saved(ctx);

Again, this really needs fixing. Preferably - as a separate commit preceding
this series, so that it could be backported. simple_read_from_buffer() is
a blocking operation. Yes, I understand that mainline has the same bug;
it really does need to be fixed and having to backport this series is not
a good idea, for obvious reasons.

2020-04-28 02:54:02

by Jeremy Kerr

[permalink] [raw]
Subject: Re: [PATCH 1/5] powerpc/spufs: simplify spufs core dumping

Hi Al & Christoph,

> Again, this really needs fixing. Preferably - as a separate commit
> preceding this series, so that it could be
> backported. simple_read_from_buffer() is a blocking operation.

I'll put together a patch that fixes this.

Christoph: I'll do it in a way that matches your changes to the _read
functions, so hopefully those hunks would just drop from your change,
leaving only the _dump additions. Would that work?

Cheers,


Jeremy

2020-04-28 07:01:05

by Christoph Hellwig

[permalink] [raw]
Subject: Re: [PATCH 1/5] powerpc/spufs: simplify spufs core dumping

On Tue, Apr 28, 2020 at 10:51:56AM +0800, Jeremy Kerr wrote:
> Hi Al & Christoph,
>
> > Again, this really needs fixing. Preferably - as a separate commit
> > preceding this series, so that it could be
> > backported. simple_read_from_buffer() is a blocking operation.
>
> I'll put together a patch that fixes this.
>
> Christoph: I'll do it in a way that matches your changes to the _read
> functions, so hopefully those hunks would just drop from your change,
> leaving only the _dump additions. Would that work?

Sure.

2020-04-28 12:06:51

by Jeremy Kerr

[permalink] [raw]
Subject: [RFC PATCH] powerpc/spufs: fix copy_to_user while atomic

Currently, we may perform a copy_to_user (through
simple_read_from_buffer()) while holding a context's register_lock,
while accessing the context save area.

This change uses a temporary buffers for the context save area data,
which we then pass to simple_read_from_buffer.

Signed-off-by: Jeremy Kerr <[email protected]>
---

Christoph - this fixes the copy_to_user while atomic, hopefully with
only minimal distruption to your series.

---
arch/powerpc/platforms/cell/spufs/file.c | 110 +++++++++++++++--------
1 file changed, 74 insertions(+), 36 deletions(-)

diff --git a/arch/powerpc/platforms/cell/spufs/file.c b/arch/powerpc/platforms/cell/spufs/file.c
index c0f950a3f4e1..c62d77ddaf7d 100644
--- a/arch/powerpc/platforms/cell/spufs/file.c
+++ b/arch/powerpc/platforms/cell/spufs/file.c
@@ -1978,8 +1978,9 @@ static ssize_t __spufs_mbox_info_read(struct spu_context *ctx,
static ssize_t spufs_mbox_info_read(struct file *file, char __user *buf,
size_t len, loff_t *pos)
{
- int ret;
struct spu_context *ctx = file->private_data;
+ u32 stat, data;
+ int ret;

if (!access_ok(buf, len))
return -EFAULT;
@@ -1988,11 +1989,16 @@ static ssize_t spufs_mbox_info_read(struct file *file, char __user *buf,
if (ret)
return ret;
spin_lock(&ctx->csa.register_lock);
- ret = __spufs_mbox_info_read(ctx, buf, len, pos);
+ stat = ctx->csa.prob.mb_stat_R;
+ data = ctx->csa.prob.pu_mb_R;
spin_unlock(&ctx->csa.register_lock);
spu_release_saved(ctx);

- return ret;
+ /* EOF if there's no entry in the mbox */
+ if (!(stat & 0x0000ff))
+ return 0;
+
+ return simple_read_from_buffer(buf, len, pos, &data, sizeof(data));
}

static const struct file_operations spufs_mbox_info_fops = {
@@ -2019,6 +2025,7 @@ static ssize_t spufs_ibox_info_read(struct file *file, char __user *buf,
size_t len, loff_t *pos)
{
struct spu_context *ctx = file->private_data;
+ u32 stat, data;
int ret;

if (!access_ok(buf, len))
@@ -2028,11 +2035,16 @@ static ssize_t spufs_ibox_info_read(struct file *file, char __user *buf,
if (ret)
return ret;
spin_lock(&ctx->csa.register_lock);
- ret = __spufs_ibox_info_read(ctx, buf, len, pos);
+ stat = ctx->csa.prob.mb_stat_R;
+ data = ctx->csa.priv2.puint_mb_R;
spin_unlock(&ctx->csa.register_lock);
spu_release_saved(ctx);

- return ret;
+ /* EOF if there's no entry in the ibox */
+ if (!(stat & 0xff0000))
+ return 0;
+
+ return simple_read_from_buffer(buf, len, pos, &data, sizeof(data));
}

static const struct file_operations spufs_ibox_info_fops = {
@@ -2041,6 +2053,11 @@ static const struct file_operations spufs_ibox_info_fops = {
.llseek = generic_file_llseek,
};

+static size_t spufs_wbox_info_cnt(struct spu_context *ctx)
+{
+ return (4 - ((ctx->csa.prob.mb_stat_R & 0x00ff00) >> 8)) * sizeof(u32);
+}
+
static ssize_t __spufs_wbox_info_read(struct spu_context *ctx,
char __user *buf, size_t len, loff_t *pos)
{
@@ -2049,7 +2066,7 @@ static ssize_t __spufs_wbox_info_read(struct spu_context *ctx,
u32 wbox_stat;

wbox_stat = ctx->csa.prob.mb_stat_R;
- cnt = 4 - ((wbox_stat & 0x00ff00) >> 8);
+ cnt = spufs_wbox_info_cnt(ctx);
for (i = 0; i < cnt; i++) {
data[i] = ctx->csa.spu_mailbox_data[i];
}
@@ -2062,7 +2079,8 @@ static ssize_t spufs_wbox_info_read(struct file *file, char __user *buf,
size_t len, loff_t *pos)
{
struct spu_context *ctx = file->private_data;
- int ret;
+ u32 data[ARRAY_SIZE(ctx->csa.spu_mailbox_data)];
+ int ret, count;

if (!access_ok(buf, len))
return -EFAULT;
@@ -2071,11 +2089,13 @@ static ssize_t spufs_wbox_info_read(struct file *file, char __user *buf,
if (ret)
return ret;
spin_lock(&ctx->csa.register_lock);
- ret = __spufs_wbox_info_read(ctx, buf, len, pos);
+ count = spufs_wbox_info_cnt(ctx);
+ memcpy(&data, &ctx->csa.spu_mailbox_data, sizeof(data));
spin_unlock(&ctx->csa.register_lock);
spu_release_saved(ctx);

- return ret;
+ return simple_read_from_buffer(buf, len, pos, &data,
+ count * sizeof(u32));
}

static const struct file_operations spufs_wbox_info_fops = {
@@ -2084,20 +2104,19 @@ static const struct file_operations spufs_wbox_info_fops = {
.llseek = generic_file_llseek,
};

-static ssize_t __spufs_dma_info_read(struct spu_context *ctx,
- char __user *buf, size_t len, loff_t *pos)
+static void ___spufs_dma_info_read(struct spu_context *ctx,
+ struct spu_dma_info *info)
{
- struct spu_dma_info info;
struct mfc_cq_sr *qp, *spuqp;
int i;

- info.dma_info_type = ctx->csa.priv2.spu_tag_status_query_RW;
- info.dma_info_mask = ctx->csa.lscsa->tag_mask.slot[0];
- info.dma_info_status = ctx->csa.spu_chnldata_RW[24];
- info.dma_info_stall_and_notify = ctx->csa.spu_chnldata_RW[25];
- info.dma_info_atomic_command_status = ctx->csa.spu_chnldata_RW[27];
+ info->dma_info_type = ctx->csa.priv2.spu_tag_status_query_RW;
+ info->dma_info_mask = ctx->csa.lscsa->tag_mask.slot[0];
+ info->dma_info_status = ctx->csa.spu_chnldata_RW[24];
+ info->dma_info_stall_and_notify = ctx->csa.spu_chnldata_RW[25];
+ info->dma_info_atomic_command_status = ctx->csa.spu_chnldata_RW[27];
for (i = 0; i < 16; i++) {
- qp = &info.dma_info_command_data[i];
+ qp = &info->dma_info_command_data[i];
spuqp = &ctx->csa.priv2.spuq[i];

qp->mfc_cq_data0_RW = spuqp->mfc_cq_data0_RW;
@@ -2105,6 +2124,14 @@ static ssize_t __spufs_dma_info_read(struct spu_context *ctx,
qp->mfc_cq_data2_RW = spuqp->mfc_cq_data2_RW;
qp->mfc_cq_data3_RW = spuqp->mfc_cq_data3_RW;
}
+}
+
+static ssize_t __spufs_dma_info_read(struct spu_context *ctx,
+ char __user *buf, size_t len, loff_t *pos)
+{
+ struct spu_dma_info info;
+
+ ___spufs_dma_info_read(ctx, &info);

return simple_read_from_buffer(buf, len, pos, &info,
sizeof info);
@@ -2114,6 +2141,7 @@ static ssize_t spufs_dma_info_read(struct file *file, char __user *buf,
size_t len, loff_t *pos)
{
struct spu_context *ctx = file->private_data;
+ struct spu_dma_info info;
int ret;

if (!access_ok(buf, len))
@@ -2123,11 +2151,12 @@ static ssize_t spufs_dma_info_read(struct file *file, char __user *buf,
if (ret)
return ret;
spin_lock(&ctx->csa.register_lock);
- ret = __spufs_dma_info_read(ctx, buf, len, pos);
+ ___spufs_dma_info_read(ctx, &info);
spin_unlock(&ctx->csa.register_lock);
spu_release_saved(ctx);

- return ret;
+ return simple_read_from_buffer(buf, len, pos, &info,
+ sizeof(info));
}

static const struct file_operations spufs_dma_info_fops = {
@@ -2136,13 +2165,31 @@ static const struct file_operations spufs_dma_info_fops = {
.llseek = no_llseek,
};

+static void ___spufs_proxydma_info_read(struct spu_context *ctx,
+ struct spu_proxydma_info *info)
+{
+ int i;
+
+ info->proxydma_info_type = ctx->csa.prob.dma_querytype_RW;
+ info->proxydma_info_mask = ctx->csa.prob.dma_querymask_RW;
+ info->proxydma_info_status = ctx->csa.prob.dma_tagstatus_R;
+
+ for (i = 0; i < 8; i++) {
+ struct mfc_cq_sr *qp = &info->proxydma_info_command_data[i];
+ struct mfc_cq_sr *puqp = &ctx->csa.priv2.puq[i];
+
+ qp->mfc_cq_data0_RW = puqp->mfc_cq_data0_RW;
+ qp->mfc_cq_data1_RW = puqp->mfc_cq_data1_RW;
+ qp->mfc_cq_data2_RW = puqp->mfc_cq_data2_RW;
+ qp->mfc_cq_data3_RW = puqp->mfc_cq_data3_RW;
+ }
+}
+
static ssize_t __spufs_proxydma_info_read(struct spu_context *ctx,
char __user *buf, size_t len, loff_t *pos)
{
struct spu_proxydma_info info;
- struct mfc_cq_sr *qp, *puqp;
int ret = sizeof info;
- int i;

if (len < ret)
return -EINVAL;
@@ -2150,18 +2197,7 @@ static ssize_t __spufs_proxydma_info_read(struct spu_context *ctx,
if (!access_ok(buf, len))
return -EFAULT;

- info.proxydma_info_type = ctx->csa.prob.dma_querytype_RW;
- info.proxydma_info_mask = ctx->csa.prob.dma_querymask_RW;
- info.proxydma_info_status = ctx->csa.prob.dma_tagstatus_R;
- for (i = 0; i < 8; i++) {
- qp = &info.proxydma_info_command_data[i];
- puqp = &ctx->csa.priv2.puq[i];
-
- qp->mfc_cq_data0_RW = puqp->mfc_cq_data0_RW;
- qp->mfc_cq_data1_RW = puqp->mfc_cq_data1_RW;
- qp->mfc_cq_data2_RW = puqp->mfc_cq_data2_RW;
- qp->mfc_cq_data3_RW = puqp->mfc_cq_data3_RW;
- }
+ ___spufs_proxydma_info_read(ctx, &info);

return simple_read_from_buffer(buf, len, pos, &info,
sizeof info);
@@ -2171,17 +2207,19 @@ static ssize_t spufs_proxydma_info_read(struct file *file, char __user *buf,
size_t len, loff_t *pos)
{
struct spu_context *ctx = file->private_data;
+ struct spu_proxydma_info info;
int ret;

ret = spu_acquire_saved(ctx);
if (ret)
return ret;
spin_lock(&ctx->csa.register_lock);
- ret = __spufs_proxydma_info_read(ctx, buf, len, pos);
+ ___spufs_proxydma_info_read(ctx, &info);
spin_unlock(&ctx->csa.register_lock);
spu_release_saved(ctx);

- return ret;
+ return simple_read_from_buffer(buf, len, pos, &info,
+ sizeof(info));
}

static const struct file_operations spufs_proxydma_info_fops = {
--
2.17.1

2020-04-28 13:56:36

by Christoph Hellwig

[permalink] [raw]
Subject: Re: [RFC PATCH] powerpc/spufs: fix copy_to_user while atomic

On Tue, Apr 28, 2020 at 08:02:07PM +0800, Jeremy Kerr wrote:
> Currently, we may perform a copy_to_user (through
> simple_read_from_buffer()) while holding a context's register_lock,
> while accessing the context save area.
>
> This change uses a temporary buffers for the context save area data,
> which we then pass to simple_read_from_buffer.
>
> Signed-off-by: Jeremy Kerr <[email protected]>
> ---
>
> Christoph - this fixes the copy_to_user while atomic, hopefully with
> only minimal distruption to your series.

I recognize plenty of sniplets from that :) Your patch looks good
to me:

Reviewed-by: Christoph Hellwig <[email protected]>

2020-04-28 16:02:43

by Arnd Bergmann

[permalink] [raw]
Subject: Re: [RFC PATCH] powerpc/spufs: fix copy_to_user while atomic

On Tue, Apr 28, 2020 at 2:05 PM Jeremy Kerr <[email protected]> wrote:
>
> Currently, we may perform a copy_to_user (through
> simple_read_from_buffer()) while holding a context's register_lock,
> while accessing the context save area.
>
> This change uses a temporary buffers for the context save area data,
> which we then pass to simple_read_from_buffer.
>
> Signed-off-by: Jeremy Kerr <[email protected]>
> ---

Thanks for fixing this!

I wonder how far it should be backported, given that this has been broken for
14 years now.

Fixes: bf1ab978be23 ("[POWERPC] coredump: Add SPU elf notes to coredump.")
Reviewed-by: Arnd Bergmann <[email protected]>

2020-04-28 17:15:57

by Christoph Hellwig

[permalink] [raw]
Subject: Re: [RFC PATCH] powerpc/spufs: fix copy_to_user while atomic

FYI, these little hunks reduce the difference to my version, maybe
you can fold them in?

diff --git a/arch/powerpc/platforms/cell/spufs/file.c b/arch/powerpc/platforms/cell/spufs/file.c
index c62d77ddaf7d3..1861436a6091d 100644
--- a/arch/powerpc/platforms/cell/spufs/file.c
+++ b/arch/powerpc/platforms/cell/spufs/file.c
@@ -2107,7 +2107,6 @@ static const struct file_operations spufs_wbox_info_fops = {
static void ___spufs_dma_info_read(struct spu_context *ctx,
struct spu_dma_info *info)
{
- struct mfc_cq_sr *qp, *spuqp;
int i;

info->dma_info_type = ctx->csa.priv2.spu_tag_status_query_RW;
@@ -2116,8 +2115,8 @@ static void ___spufs_dma_info_read(struct spu_context *ctx,
info->dma_info_stall_and_notify = ctx->csa.spu_chnldata_RW[25];
info->dma_info_atomic_command_status = ctx->csa.spu_chnldata_RW[27];
for (i = 0; i < 16; i++) {
- qp = &info->dma_info_command_data[i];
- spuqp = &ctx->csa.priv2.spuq[i];
+ struct mfc_cq_sr *qp = &info->dma_info_command_data[i];
+ struct mfc_cq_sr *qp, *spuqp = &ctx->csa.priv2.spuq[i];

qp->mfc_cq_data0_RW = spuqp->mfc_cq_data0_RW;
qp->mfc_cq_data1_RW = spuqp->mfc_cq_data1_RW;
@@ -2166,7 +2165,7 @@ static const struct file_operations spufs_dma_info_fops = {
};

static void ___spufs_proxydma_info_read(struct spu_context *ctx,
- struct spu_proxydma_info *info)
+ struct spu_proxydma_info *info)
{
int i;

2020-04-29 01:39:35

by Jeremy Kerr

[permalink] [raw]
Subject: Re: [RFC PATCH] powerpc/spufs: fix copy_to_user while atomic

Hi Christoph,

> FYI, these little hunks reduce the difference to my version, maybe
> you can fold them in?

Sure, no problem.

How do you want to coordinate these? I can submit mine through mpe, but
that may make it tricky to synchronise with your changes. Or, you can
include this change in your series if you prefer.

Cheers,


Jeremy


2020-04-29 06:09:44

by Christoph Hellwig

[permalink] [raw]
Subject: Re: [RFC PATCH] powerpc/spufs: fix copy_to_user while atomic

On Wed, Apr 29, 2020 at 09:36:30AM +0800, Jeremy Kerr wrote:
> Hi Christoph,
>
> > FYI, these little hunks reduce the difference to my version, maybe
> > you can fold them in?
>
> Sure, no problem.
>
> How do you want to coordinate these? I can submit mine through mpe, but
> that may make it tricky to synchronise with your changes. Or, you can
> include this change in your series if you prefer.

Maybe you can feed your patch directly to Linus through Michael
ASAP, and I'll wait for that before resubmitting this series?

2020-04-29 06:15:55

by Christoph Hellwig

[permalink] [raw]
Subject: Re: [RFC PATCH] powerpc/spufs: fix copy_to_user while atomic

On Wed, Apr 29, 2020 at 08:05:53AM +0200, Christoph Hellwig wrote:
> On Wed, Apr 29, 2020 at 09:36:30AM +0800, Jeremy Kerr wrote:
> > Hi Christoph,
> >
> > > FYI, these little hunks reduce the difference to my version, maybe
> > > you can fold them in?
> >
> > Sure, no problem.
> >
> > How do you want to coordinate these? I can submit mine through mpe, but
> > that may make it tricky to synchronise with your changes. Or, you can
> > include this change in your series if you prefer.
>
> Maybe you can feed your patch directly to Linus through Michael
> ASAP, and I'll wait for that before resubmitting this series?

Btw, turns out my fold patch didn't actually compile without the
rebased patch on top, sorry. Here is the proper one:

diff --git a/arch/powerpc/platforms/cell/spufs/file.c b/arch/powerpc/platforms/cell/spufs/file.c
index c62d77ddaf7d3..b4e1ef650b406 100644
--- a/arch/powerpc/platforms/cell/spufs/file.c
+++ b/arch/powerpc/platforms/cell/spufs/file.c
@@ -2107,7 +2107,6 @@ static const struct file_operations spufs_wbox_info_fops = {
static void ___spufs_dma_info_read(struct spu_context *ctx,
struct spu_dma_info *info)
{
- struct mfc_cq_sr *qp, *spuqp;
int i;

info->dma_info_type = ctx->csa.priv2.spu_tag_status_query_RW;
@@ -2116,8 +2115,8 @@ static void ___spufs_dma_info_read(struct spu_context *ctx,
info->dma_info_stall_and_notify = ctx->csa.spu_chnldata_RW[25];
info->dma_info_atomic_command_status = ctx->csa.spu_chnldata_RW[27];
for (i = 0; i < 16; i++) {
- qp = &info->dma_info_command_data[i];
- spuqp = &ctx->csa.priv2.spuq[i];
+ struct mfc_cq_sr *qp = &info->dma_info_command_data[i];
+ struct mfc_cq_sr *spuqp = &ctx->csa.priv2.spuq[i];

qp->mfc_cq_data0_RW = spuqp->mfc_cq_data0_RW;
qp->mfc_cq_data1_RW = spuqp->mfc_cq_data1_RW;
@@ -2166,7 +2165,7 @@ static const struct file_operations spufs_dma_info_fops = {
};

static void ___spufs_proxydma_info_read(struct spu_context *ctx,
- struct spu_proxydma_info *info)
+ struct spu_proxydma_info *info)
{
int i;

2020-04-29 06:17:19

by Christoph Hellwig

[permalink] [raw]
Subject: Re: [RFC PATCH] powerpc/spufs: fix copy_to_user while atomic

And another one that should go on top of this one to address Al's other
compaint:

---
From 1b7ced3de0b3a4addec61f61ac5278c3ff141657 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <[email protected]>
Date: Wed, 22 Apr 2020 09:05:30 +0200
Subject: powerpc/spufs: stop using access_ok

Just use the proper non __-prefixed get/put_user variants where that is
not done yet.

Signed-off-by: Christoph Hellwig <[email protected]>
---
arch/powerpc/platforms/cell/spufs/file.c | 42 +++++-------------------
1 file changed, 8 insertions(+), 34 deletions(-)

diff --git a/arch/powerpc/platforms/cell/spufs/file.c b/arch/powerpc/platforms/cell/spufs/file.c
index b4e1ef650b406..cd7d10f27fad1 100644
--- a/arch/powerpc/platforms/cell/spufs/file.c
+++ b/arch/powerpc/platforms/cell/spufs/file.c
@@ -590,17 +590,12 @@ static ssize_t spufs_mbox_read(struct file *file, char __user *buf,
size_t len, loff_t *pos)
{
struct spu_context *ctx = file->private_data;
- u32 mbox_data, __user *udata;
+ u32 mbox_data, __user *udata = (void __user *)buf;
ssize_t count;

if (len < 4)
return -EINVAL;

- if (!access_ok(buf, len))
- return -EFAULT;
-
- udata = (void __user *)buf;
-
count = spu_acquire(ctx);
if (count)
return count;
@@ -616,7 +611,7 @@ static ssize_t spufs_mbox_read(struct file *file, char __user *buf,
* but still need to return the data we have
* read successfully so far.
*/
- ret = __put_user(mbox_data, udata);
+ ret = put_user(mbox_data, udata);
if (ret) {
if (!count)
count = -EFAULT;
@@ -698,17 +693,12 @@ static ssize_t spufs_ibox_read(struct file *file, char __user *buf,
size_t len, loff_t *pos)
{
struct spu_context *ctx = file->private_data;
- u32 ibox_data, __user *udata;
+ u32 ibox_data, __user *udata = (void __user *)buf;
ssize_t count;

if (len < 4)
return -EINVAL;

- if (!access_ok(buf, len))
- return -EFAULT;
-
- udata = (void __user *)buf;
-
count = spu_acquire(ctx);
if (count)
goto out;
@@ -727,7 +717,7 @@ static ssize_t spufs_ibox_read(struct file *file, char __user *buf,
}

/* if we can't write at all, return -EFAULT */
- count = __put_user(ibox_data, udata);
+ count = put_user(ibox_data, udata);
if (count)
goto out_unlock;

@@ -741,7 +731,7 @@ static ssize_t spufs_ibox_read(struct file *file, char __user *buf,
* but still need to return the data we have
* read successfully so far.
*/
- ret = __put_user(ibox_data, udata);
+ ret = put_user(ibox_data, udata);
if (ret)
break;
}
@@ -836,17 +826,13 @@ static ssize_t spufs_wbox_write(struct file *file, const char __user *buf,
size_t len, loff_t *pos)
{
struct spu_context *ctx = file->private_data;
- u32 wbox_data, __user *udata;
+ u32 wbox_data, __user *udata = (void __user *)buf;
ssize_t count;

if (len < 4)
return -EINVAL;

- udata = (void __user *)buf;
- if (!access_ok(buf, len))
- return -EFAULT;
-
- if (__get_user(wbox_data, udata))
+ if (get_user(wbox_data, udata))
return -EFAULT;

count = spu_acquire(ctx);
@@ -873,7 +859,7 @@ static ssize_t spufs_wbox_write(struct file *file, const char __user *buf,
/* write as much as possible */
for (count = 4, udata++; (count + 4) <= len; count += 4, udata++) {
int ret;
- ret = __get_user(wbox_data, udata);
+ ret = get_user(wbox_data, udata);
if (ret)
break;

@@ -1982,9 +1968,6 @@ static ssize_t spufs_mbox_info_read(struct file *file, char __user *buf,
u32 stat, data;
int ret;

- if (!access_ok(buf, len))
- return -EFAULT;
-
ret = spu_acquire_saved(ctx);
if (ret)
return ret;
@@ -2028,9 +2011,6 @@ static ssize_t spufs_ibox_info_read(struct file *file, char __user *buf,
u32 stat, data;
int ret;

- if (!access_ok(buf, len))
- return -EFAULT;
-
ret = spu_acquire_saved(ctx);
if (ret)
return ret;
@@ -2082,9 +2062,6 @@ static ssize_t spufs_wbox_info_read(struct file *file, char __user *buf,
u32 data[ARRAY_SIZE(ctx->csa.spu_mailbox_data)];
int ret, count;

- if (!access_ok(buf, len))
- return -EFAULT;
-
ret = spu_acquire_saved(ctx);
if (ret)
return ret;
@@ -2143,9 +2120,6 @@ static ssize_t spufs_dma_info_read(struct file *file, char __user *buf,
struct spu_dma_info info;
int ret;

- if (!access_ok(buf, len))
- return -EFAULT;
-
ret = spu_acquire_saved(ctx);
if (ret)
return ret;
--
2.26.2

2020-04-29 06:35:04

by Jeremy Kerr

[permalink] [raw]
Subject: Re: [RFC PATCH] powerpc/spufs: fix copy_to_user while atomic

Hi Christoph,

> And another one that should go on top of this one to address Al's other
> compaint:

Yeah, I was pondering that one. The access_ok() is kinda redundant, but
it does avoid forcing a SPU context save on those errors.

However, it's not like we really need to optimise for the case of
invalid addresses from userspace. So, I'll include this change in the
submission to Michael's tree. Arnd - let me know if you have any
objections.

Cheers,


Jeremy


2020-04-29 07:47:02

by Arnd Bergmann

[permalink] [raw]
Subject: Re: [RFC PATCH] powerpc/spufs: fix copy_to_user while atomic

On Wed, Apr 29, 2020 at 8:33 AM Jeremy Kerr <[email protected]> wrote:
>
> Hi Christoph,
>
> > And another one that should go on top of this one to address Al's other
> > compaint:
>
> Yeah, I was pondering that one. The access_ok() is kinda redundant, but
> it does avoid forcing a SPU context save on those errors.
>
> However, it's not like we really need to optimise for the case of
> invalid addresses from userspace. So, I'll include this change in the
> submission to Michael's tree. Arnd - let me know if you have any
> objections.

Sounds good. A lot of the access_ok() checks in the kernel are redundant
or wrong, I think it makes a lot of sense to remove these.

Arnd