LinuxLists.cc - [PATCH 0/2] Embedding Position Independent Executables

2016-04-03 07:24:22

Subject: [PATCH 0/2] Embedding Position Independent Executables

Hi,

This series tries to revive the many series trying to achieve the same thing.

I've tried numerous approaches and while using the kernel module loader is
actually quite convenient from a relocation point of view it is quite overkill
and also it is quite often too late as a lot of the arch specific PM code assume
that it is running at boot time, befor having access to any filesystem.

I've chosen to be less generic than what Russ did and only handle ARM. I reused
the API he defined but I actually went closer to his first implementation by
compiling and embedding a real PIE that doesn't actually need relocations (gcc
seems to be better at it thanks to ASLR).

In this series, I'm also converting the AT91 suspend code to use that
infrastructure as it is quite simple but I also toyed with more complex
functions.

The current limitation is that is doesn't actually tries to handle big endian
and I didn't test thumb (and this will probably require more work to get that
working reliably).

Also, to be more useful prppoer handling of a stack has to be added (this is not
too difficult and is planned) and will be enough to get rk3288 suspend/resume and
DDR timing changes working.

Alexandre Belloni (2):
ARM: PIE infrastructure
ARM: at91: pm: switch to the PIE infrastructure

arch/arm/Kconfig | 2 +
arch/arm/Makefile | 1 +
arch/arm/mach-at91/Kconfig | 1 +
arch/arm/mach-at91/Makefile | 2 +-
arch/arm/mach-at91/pm.c | 31 ++--
arch/arm/mach-at91/pm/.gitignore | 2 +
arch/arm/mach-at91/pm/Makefile | 3 +
arch/arm/mach-at91/pm/atmel_pm.c | 97 +++++++++++
arch/arm/mach-at91/pm_suspend.S | 338 ---------------------------------------
arch/arm/pie/Kconfig | 8 +
arch/arm/pie/Makefile | 1 +
arch/arm/pie/Makefile.pie | 70 ++++++++
arch/arm/pie/lib/empty.c | 15 ++
arch/arm/pie/pie.c | 97 +++++++++++
arch/arm/pie/pie.lds.S | 40 +++++
include/linux/pie.h | 159 ++++++++++++++++++
16 files changed, 507 insertions(+), 360 deletions(-)
create mode 100644 arch/arm/mach-at91/pm/.gitignore
create mode 100644 arch/arm/mach-at91/pm/Makefile
create mode 100644 arch/arm/mach-at91/pm/atmel_pm.c
delete mode 100644 arch/arm/mach-at91/pm_suspend.S
create mode 100644 arch/arm/pie/Kconfig
create mode 100644 arch/arm/pie/Makefile
create mode 100644 arch/arm/pie/Makefile.pie
create mode 100644 arch/arm/pie/lib/empty.c
create mode 100644 arch/arm/pie/pie.c
create mode 100644 arch/arm/pie/pie.lds.S
create mode 100644 include/linux/pie.h

--
2.8.0.rc3

2016-04-03 07:24:24

by Alexandre Belloni

[permalink] [raw]

Subject: [PATCH 1/2] ARM: PIE infrastructure

Add support for embedding position independent executables (PIE) in the
kernel. Those PIEs can then be loaded into memory allocated using genalloc.
For example, this allows running code from SRAM which is usually needed for
suspend/resume or to change the DDR timings. That code is usually written
in assembly and can now be developed in C.

Signed-off-by: Alexandre Belloni <[email protected]>
---
arch/arm/Kconfig | 2 +
arch/arm/Makefile | 1 +
arch/arm/pie/Kconfig | 8 +++
arch/arm/pie/Makefile | 1 +
arch/arm/pie/Makefile.pie | 70 ++++++++++++++++++++
arch/arm/pie/lib/empty.c | 15 +++++
arch/arm/pie/pie.c | 97 ++++++++++++++++++++++++++++
arch/arm/pie/pie.lds.S | 40 ++++++++++++
include/linux/pie.h | 159 ++++++++++++++++++++++++++++++++++++++++++++++
9 files changed, 393 insertions(+)
create mode 100644 arch/arm/pie/Kconfig
create mode 100644 arch/arm/pie/Makefile
create mode 100644 arch/arm/pie/Makefile.pie
create mode 100644 arch/arm/pie/lib/empty.c
create mode 100644 arch/arm/pie/pie.c
create mode 100644 arch/arm/pie/pie.lds.S
create mode 100644 include/linux/pie.h

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index cdfa6c2b7626..e671ade2d86a 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -2148,3 +2148,5 @@ endif
source "lib/Kconfig"

source "arch/arm/kvm/Kconfig"
+
+source "arch/arm/pie/Kconfig"
diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index 8c3ce2ac44c4..c39e6aef6ff7 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -281,6 +281,7 @@ core-$(CONFIG_VFP) += arch/arm/vfp/
core-$(CONFIG_XEN) += arch/arm/xen/
core-$(CONFIG_KVM_ARM_HOST) += arch/arm/kvm/
core-$(CONFIG_VDSO) += arch/arm/vdso/
+core-$(CONFIG_PIE) += arch/arm/pie/

# If we have a machine-specific directory, then include it in the build.
core-y += arch/arm/kernel/ arch/arm/mm/ arch/arm/common/
diff --git a/arch/arm/pie/Kconfig b/arch/arm/pie/Kconfig
new file mode 100644
index 000000000000..d76122140561
--- /dev/null
+++ b/arch/arm/pie/Kconfig
@@ -0,0 +1,8 @@
+config PIE
+ bool
+ help
+ This option adds support for embedding position indepentant (PIE)
+ executables into the kernel. The PIEs can then be copied into
+ genalloc regions such as SRAM and executed. Some platforms require
+ this for suspend/resume support.
+
diff --git a/arch/arm/pie/Makefile b/arch/arm/pie/Makefile
new file mode 100644
index 000000000000..d1a6a823e431
--- /dev/null
+++ b/arch/arm/pie/Makefile
@@ -0,0 +1 @@
+obj-y += pie.o
diff --git a/arch/arm/pie/Makefile.pie b/arch/arm/pie/Makefile.pie
new file mode 100644
index 000000000000..709a51be1578
--- /dev/null
+++ b/arch/arm/pie/Makefile.pie
@@ -0,0 +1,70 @@
+obj-y := pie.bin.elf
+
+# Report unresolved symbol references
+ldflags-y += --no-undefined
+# Delete all temporary local symbols
+ldflags-y += -X
+
+# Reset objcopy flags
+OBJCOPYFLAGS =
+
+$(obj)/empty.o: arch/arm/pie/lib/empty.c FORCE
+ $(call if_changed_rule,cc_o_c)
+
+# Reference gcc builtins for use in PIE with __pie_
+$(obj)/pie_rename.syms: $(obj)/empty.o
+ @$(NM) $^ | awk '{if ($$3) print $$3,"__pie_"$$3}' > $@
+
+# For embedding address of the symbols copied from the PIE into the kernel
+$(obj)/pie.syms: $(obj)/pie.elf
+ @$(NM) $^ | awk '{if ($$3 && $$2 == toupper($$2)) print $$3,"=","0x"$$1";"}' > $@
+
+# Collect together the libpie objects
+LDFLAGS_libpie_stage1.o += -r
+
+$(obj)/libpie_stage1.o: $(obj)/empty.o
+ $(call if_changed,ld)
+
+# Rename the libpie gcc builtins with a __pie_ prefix
+OBJCOPYFLAGS_libpie_stage2.o += --redefine-syms=$(obj)/pie_rename.syms
+
+$(obj)/libpie_stage2.o: $(obj)/libpie_stage1.o
+ $(call if_changed,objcopy)
+
+CFLAGS_$(PIE_NAME).o += -fPIE
+
+OBJCOPYFLAGS_pie_stage1.o += --redefine-syms=$(obj)/pie_rename.syms
+$(obj)/pie_stage1.o: $(obj)/$(PIE_NAME).o $(obj)/pie_rename.syms
+ $(call if_changed,objcopy)
+
+LDFLAGS_pie_stage2.o += -r
+
+$(obj)/pie_stage2.o: $(obj)/pie_stage1.o $(obj)/libpie_stage2.o
+ $(call if_changed,ld)
+
+SEDFLAGS_lds = s/PIE_NAME/$(PIE_NAME)/
+$(obj)/pie.lds.S: arch/arm/pie/pie.lds.S
+ @sed "$(SEDFLAGS_lds)" < $< > $@
+
+# Create the position independent executable
+LDFLAGS_pie.elf += -Bstatic -T $(obj)/pie.lds
+
+$(obj)/pie.elf: $(obj)/pie_stage2.o $(obj)/pie.lds
+ $(call if_changed,ld)
+
+# Create binary data for the kernel
+OBJCOPYFLAGS_pie.bin += -O binary
+
+$(obj)/pie.bin: $(obj)/pie.elf $(obj)/pie.syms
+ $(call if_changed,objcopy)
+
+# Import the data into the kernel
+OBJCOPYFLAGS_pie.bin.o += -B $(ARCH) -I binary -O elf32-littlearm
+
+$(obj)/pie.bin.o: $(obj)/pie.bin
+ $(call if_changed,objcopy)
+
+LDFLAGS_pie.bin.elf += --just-symbols=$(obj)/pie.syms -r
+$(obj)/pie.bin.elf: $(obj)/pie.bin.o $(obj)/pie_stage2.o
+ $(call if_changed,ld)
+
diff --git a/arch/arm/pie/lib/empty.c b/arch/arm/pie/lib/empty.c
new file mode 100644
index 000000000000..9a6d54956379
--- /dev/null
+++ b/arch/arm/pie/lib/empty.c
@@ -0,0 +1,15 @@
+void __div0(void)
+{
+};
+
+void __aeabi_unwind_cpp_pr0(void)
+{
+};
+
+void __aeabi_unwind_cpp_pr1(void)
+{
+};
+
+void __aeabi_unwind_cpp_pr2(void)
+{
+};
diff --git a/arch/arm/pie/pie.c b/arch/arm/pie/pie.c
new file mode 100644
index 000000000000..62406a54459f
--- /dev/null
+++ b/arch/arm/pie/pie.c
@@ -0,0 +1,97 @@
+/*
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/genalloc.h>
+#include <linux/pie.h>
+#include <asm/cacheflush.h>
+
+struct pie_chunk {
+ struct gen_pool *pool;
+ unsigned long addr;
+ size_t sz;
+};
+
+struct pie_chunk *__pie_load_data(struct gen_pool *pool, void *code_start,
+ void *code_end, bool phys)
+{
+ struct pie_chunk *chunk;
+ unsigned long offset;
+ int ret;
+ size_t code_sz;
+ unsigned long base;
+ phys_addr_t pbase;
+
+ chunk = kzalloc(sizeof(*chunk), GFP_KERNEL);
+ if (!chunk) {
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ code_sz = code_end - code_start;
+ chunk->pool = pool;
+ chunk->sz = code_sz;
+
+ base = gen_pool_alloc(pool, chunk->sz);
+ if (!base) {
+ ret = -ENOMEM;
+ goto err_free;
+ }
+
+ pbase = gen_pool_virt_to_phys(pool, base);
+ chunk->addr = (unsigned long)__arm_ioremap_exec(pbase, code_sz, false);
+ if (!chunk->addr) {
+ ret = -ENOMEM;
+ goto err_remap;
+ }
+
+ /* Copy chunk specific code/data */
+ fncpy((char *)chunk->addr, code_start, code_sz);
+
+ /* Calculate initial offset */
+ if (phys)
+ offset = gen_pool_virt_to_phys(pool, chunk->addr);
+ else
+ offset = chunk->addr;
+
+ return chunk;
+
+err_remap:
+ gen_pool_free(chunk->pool, chunk->addr, chunk->sz);
+
+err_free:
+ kfree(chunk);
+err:
+ return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(__pie_load_data);
+
+phys_addr_t pie_to_phys(struct pie_chunk *chunk, unsigned long addr)
+{
+ return gen_pool_virt_to_phys(chunk->pool, addr);
+}
+EXPORT_SYMBOL_GPL(pie_to_phys);
+
+void __iomem *__kern_to_pie(struct pie_chunk *chunk, void *ptr)
+{
+ uintptr_t offset = (uintptr_t)ptr;
+
+ if (offset >= chunk->sz)
+ return NULL;
+ else
+ return (void *)(chunk->addr + offset);
+}
+EXPORT_SYMBOL_GPL(__kern_to_pie);
+
+void pie_free(struct pie_chunk *chunk)
+{
+ gen_pool_free(chunk->pool, chunk->addr, chunk->sz);
+ kfree(chunk);
+}
+EXPORT_SYMBOL_GPL(pie_free);
diff --git a/arch/arm/pie/pie.lds.S b/arch/arm/pie/pie.lds.S
new file mode 100644
index 000000000000..f84391260f64
--- /dev/null
+++ b/arch/arm/pie/pie.lds.S
@@ -0,0 +1,40 @@
+OUTPUT_FORMAT("elf32-littlearm", "elf32-littlearm", "elf32-littlearm")
+OUTPUT_ARCH(arm)
+
+#include <linux/export.h>
+
+SECTIONS
+{
+ /* Don't need unwind tables */
+ /DISCARD/ : {
+ *(.ARM.exidx*)
+ *(.ARM.extab*)
+ *(.comment)
+ }
+
+ . = 0x0;
+
+ ____pie_PIE_NAME_start : {
+ VMLINUX_SYMBOL(__pie_PIE_NAME_start) = .;
+ }
+
+ .text : {
+ . = ALIGN(4);
+ KEEP(*(.text))
+ }
+
+ .rodata : { *(SORT_BY_ALIGNMENT(.rodata*)) }
+ . = ALIGN(4);
+
+ .data : {
+ *(SORT_BY_ALIGNMENT(.data*))
+ . = ALIGN(4);
+
+ *(SORT_BY_ALIGNMENT(.bss*))
+ . = ALIGN(4);
+ }
+
+ ____pie_PIE_NAME_end : {
+ VMLINUX_SYMBOL(__pie_PIE_NAME_end) = .;
+ }
+}
diff --git a/include/linux/pie.h b/include/linux/pie.h
new file mode 100644
index 000000000000..1e6f0fabd08f
--- /dev/null
+++ b/include/linux/pie.h
@@ -0,0 +1,159 @@
+/*
+ * Copyright 2013 Texas Instruments, Inc.
+ * Russ Dill <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ */
+
+#ifndef _LINUX_PIE_H
+#define _LINUX_PIE_H
+
+#include <linux/kernel.h>
+#include <linux/err.h>
+
+#include <asm/fncpy.h>
+#include <linux/bug.h>
+
+struct gen_pool;
+struct pie_chunk;
+
+#ifdef CONFIG_PIE
+
+/**
+ * __pie_load_data - load and fixup PIE code from kernel data
+ * @pool: pool to allocate memory from and copy code into
+ * @start: virtual start address in kernel of chunk specific code
+ * @end: virtual end address in kernel of chunk specific code
+ * @phys: %true to fixup to physical address of destination, %false to
+ * fixup to virtual address of destination
+ *
+ * Returns 0 on success, -EERROR otherwise
+ */
+struct pie_chunk *__pie_load_data(struct gen_pool *pool,
+ void *start, void *end, bool phys);
+
+/**
+ * pie_to_phys - translate a virtual PIE address into a physical one
+ * @chunk: identifier returned by pie_load_sections
+ * @addr: virtual address within pie chunk
+ *
+ * Returns physical address on success, -1 otherwise
+ */
+phys_addr_t pie_to_phys(struct pie_chunk *chunk, unsigned long addr);
+
+void __iomem *__kern_to_pie(struct pie_chunk *chunk, void *ptr);
+
+/**
+ * pie_free - free the pool space used by an pie chunk
+ * @chunk: identifier returned by pie_load_sections
+ */
+void pie_free(struct pie_chunk *chunk);
+
+#define __pie_load_sections(pool, name, folder, phys) ({ \
+ extern char _binary_##folder##_pie_bin_start[]; \
+ extern char __pie_##name##_start[]; \
+ extern char __pie_##name##_end[]; \
+ char *start = _binary_##folder##_pie_bin_start + (unsigned long)__pie_##name##_start; \
+ char *end = _binary_##folder##_pie_bin_start + (unsigned long)__pie_##name##_end; \
+ \
+ __pie_load_data(pool, start, end, phys); \
+})
+
+/*
+ * Required for any symbol within an PIE section that is referenced by the
+ * kernel
+ */
+#define EXPORT_PIE_SYMBOL(sym) extern typeof(sym) sym __weak
+
+#else
+
+static inline struct pie_chunk *__pie_load_data(struct gen_pool *pool,
+ void *start, void *end,
+ bool phys)
+{
+ return ERR_PTR(-EINVAL);
+}
+
+static inline phys_addr_t pie_to_phys(struct pie_chunk *chunk,
+ unsigned long addr)
+{
+ return -1;
+}
+
+static inline void __iomem *__kern_to_pie(struct pie_chunk *chunk, void *ptr)
+{
+ return NULL;
+}
+
+static inline void pie_free(struct pie_chunk *chunk)
+{
+}
+
+#define __pie_load_sections(pool, name, folder, phys) ({ ERR_PTR(-EINVAL); })
+
+#endif
+
+/**
+ * pie_load_sections - load and fixup sections associated with the given name
+ * @pool: pool to allocate memory from and copy code into
+ * fixup to virtual address of destination
+ * @name: the name given to __pie() and __pie_data() when marking
+ * data and code
+ *
+ * Returns 0 on success, -EERROR otherwise
+ */
+#define pie_load_sections(pool, name, folder) ({ \
+ __pie_load_sections(pool, name, folder, false); \
+})
+
+/**
+ * pie_load_sections_phys - load and fixup sections associated with the given
+ * name for execution with the MMU off
+ *
+ * @pool: pool to allocate memory from and copy code into
+ * fixup to virtual address of destination
+ * @name: the name given to __pie() and __pie_data() when marking
+ * data and code
+ *
+ * Returns 0 on success, -EERROR otherwise
+ */
+#define pie_load_sections_phys(pool, name, folder) ({ \
+ __pie_load_sections(pool, name, folder, true); \
+})
+
+/**
+ * kern_to_pie - convert a kernel symbol to the virtual address of where
+ * that symbol is loaded into the given PIE chunk.
+ *
+ * @chunk: identifier returned by pie_load_sections
+ * @p: symbol to convert
+ *
+ * Return type is the same as type passed
+ */
+#define kern_to_pie(chunk, p) ({ \
+ void *__ptr = (void *)(p); \
+ typeof(p) __result = (typeof(p))__kern_to_pie(chunk, __ptr); \
+ __result; \
+})
+
+/**
+ * kern_to_fn - convert a kernel function symbol to the virtual address of where
+ * that symbol is loaded into the given PIE chunk
+ *
+ * @chunk: identifier returned by pie_load_sections
+ * @funcp: function to convert
+ *
+ * Return type is the same as type passed
+ */
+#define fn_to_pie(chunk, funcp) ({ \
+ uintptr_t __kern_addr, __pie_addr; \
+ \
+ __kern_addr = (uintptr_t)funcp; \
+ __pie_addr = kern_to_pie(chunk, __kern_addr); \
+ \
+ (typeof(&funcp))(__pie_addr); \
+})
+
+#endif
--
2.8.0.rc3

2016-04-03 07:24:29

by Alexandre Belloni

[permalink] [raw]

Subject: [PATCH 2/2] ARM: at91: pm: switch to the PIE infrastructure

Using the PIE infrastructure allows to write the whole suspend/resume
functions in C instead of assembly.

The only remaining assembly instruction is wfi for armv5
It makes the code shorter and clearer.

Signed-off-by: Alexandre Belloni <[email protected]>
---
arch/arm/mach-at91/Kconfig | 1 +
arch/arm/mach-at91/Makefile | 2 +-
arch/arm/mach-at91/pm.c | 31 ++--
arch/arm/mach-at91/pm/.gitignore | 2 +
arch/arm/mach-at91/pm/Makefile | 3 +
arch/arm/mach-at91/pm/atmel_pm.c | 97 +++++++++++
arch/arm/mach-at91/pm_suspend.S | 338 ---------------------------------------
7 files changed, 114 insertions(+), 360 deletions(-)
create mode 100644 arch/arm/mach-at91/pm/.gitignore
create mode 100644 arch/arm/mach-at91/pm/Makefile
create mode 100644 arch/arm/mach-at91/pm/atmel_pm.c
delete mode 100644 arch/arm/mach-at91/pm_suspend.S

diff --git a/arch/arm/mach-at91/Kconfig b/arch/arm/mach-at91/Kconfig
index 08047afdf38e..ab430c04a699 100644
--- a/arch/arm/mach-at91/Kconfig
+++ b/arch/arm/mach-at91/Kconfig
@@ -5,6 +5,7 @@ menuconfig ARCH_AT91
select COMMON_CLK_AT91
select PINCTRL
select SOC_BUS
+ select PIE

if ARCH_AT91
config SOC_SAMA5D2
diff --git a/arch/arm/mach-at91/Makefile b/arch/arm/mach-at91/Makefile
index c5bbf8bb8c0f..062336de4f66 100644
--- a/arch/arm/mach-at91/Makefile
+++ b/arch/arm/mach-at91/Makefile
@@ -10,7 +10,7 @@ obj-$(CONFIG_SOC_SAMA5) += sama5.o

# Power Management
obj-$(CONFIG_PM) += pm.o
-obj-$(CONFIG_PM) += pm_suspend.o
+obj-$(CONFIG_PM) += pm/

ifeq ($(CONFIG_CPU_V7),y)
AFLAGS_pm_suspend.o := -march=armv7-a
diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c
index f06270198bf1..f2f2a97ee1de 100644
--- a/arch/arm/mach-at91/pm.c
+++ b/arch/arm/mach-at91/pm.c
@@ -21,6 +21,7 @@
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/of_address.h>
+#include <linux/pie.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/clk/at91_pmc.h>
@@ -56,6 +57,8 @@ static struct {

void __iomem *at91_ramc_base[2];

+static struct pie_chunk *atmel_pm_pie;
+
static int at91_pm_valid_state(suspend_state_t state)
{
switch (state) {
@@ -133,10 +136,6 @@ EXPORT_SYMBOL(at91_suspend_entering_slow_clock);
static void (*at91_suspend_sram_fn)(void __iomem *pmc, void __iomem *ramc0,
void __iomem *ramc1, int memctrl);

-extern void at91_pm_suspend_in_sram(void __iomem *pmc, void __iomem *ramc0,
- void __iomem *ramc1, int memctrl);
-extern u32 at91_pm_suspend_in_sram_sz;
-
static void at91_pm_suspend(suspend_state_t state)
{
unsigned int pm_data = at91_pm_data.memctrl;
@@ -370,11 +369,12 @@ void at91sam9_idle(void)
cpu_do_idle();
}

+extern void atmel_pm_suspend(void __iomem *pmc, void __iomem *ramc0,
+ void __iomem *ramc1, int memctrl);
+
static void __init at91_pm_sram_init(void)
{
struct gen_pool *sram_pool;
- phys_addr_t sram_pbase;
- unsigned long sram_base;
struct device_node *node;
struct platform_device *pdev = NULL;

@@ -397,23 +397,12 @@ static void __init at91_pm_sram_init(void)
return;
}

- sram_base = gen_pool_alloc(sram_pool, at91_pm_suspend_in_sram_sz);
- if (!sram_base) {
- pr_warn("%s: unable to alloc sram!\n", __func__);
+ atmel_pm_pie = pie_load_sections(sram_pool, atmel_pm,
+ arch_arm_mach_at91_pm);
+ if (IS_ERR(atmel_pm_pie))
return;
- }
-
- sram_pbase = gen_pool_virt_to_phys(sram_pool, sram_base);
- at91_suspend_sram_fn = __arm_ioremap_exec(sram_pbase,
- at91_pm_suspend_in_sram_sz, false);
- if (!at91_suspend_sram_fn) {
- pr_warn("SRAM: Could not map\n");
- return;
- }

- /* Copy the pm suspend handler to SRAM */
- at91_suspend_sram_fn = fncpy(at91_suspend_sram_fn,
- &at91_pm_suspend_in_sram, at91_pm_suspend_in_sram_sz);
+ at91_suspend_sram_fn = fn_to_pie(atmel_pm_pie, atmel_pm_suspend);
}

static const struct of_device_id atmel_pmc_ids[] __initconst = {
diff --git a/arch/arm/mach-at91/pm/.gitignore b/arch/arm/mach-at91/pm/.gitignore
new file mode 100644
index 000000000000..1cb8879eb0bf
--- /dev/null
+++ b/arch/arm/mach-at91/pm/.gitignore
@@ -0,0 +1,2 @@
+*.lds*
+*.syms
diff --git a/arch/arm/mach-at91/pm/Makefile b/arch/arm/mach-at91/pm/Makefile
new file mode 100644
index 000000000000..c12d54862c10
--- /dev/null
+++ b/arch/arm/mach-at91/pm/Makefile
@@ -0,0 +1,3 @@
+PIE_NAME := atmel_pm
+
+include arch/arm/pie/Makefile.pie
diff --git a/arch/arm/mach-at91/pm/atmel_pm.c b/arch/arm/mach-at91/pm/atmel_pm.c
new file mode 100644
index 000000000000..7f391addd2da
--- /dev/null
+++ b/arch/arm/mach-at91/pm/atmel_pm.c
@@ -0,0 +1,97 @@
+#include <linux/io.h>
+#include <linux/clk/at91_pmc.h>
+#include <linux/mfd/syscon/atmel-mc.h>
+#include <linux/pie.h>
+#include "../pm.h"
+
+#define SRAMC_SELF_FRESH_ACTIVE 0x01
+#define SRAMC_SELF_FRESH_EXIT 0x00
+
+static void at91_sramc_self_refresh(unsigned int is_active,
+ unsigned int memtype,
+ void __iomem *sdramc_base,
+ void __iomem *sdramc_base1)
+{
+ static unsigned int lpr, mdr, lpr1, mdr1;
+
+ switch (memtype) {
+ case AT91_MEMCTRL_MC:
+ /*
+ * at91rm9200 Memory controller
+ */
+ if (is_active)
+ __raw_writel(1, sdramc_base + AT91_MC_SDRAMC_SRR);
+ break;
+
+ case AT91_MEMCTRL_DDRSDR:
+ if (is_active) {
+ mdr = __raw_readl(sdramc_base + AT91_DDRSDRC_MDR);
+ lpr = __raw_readl(sdramc_base + AT91_DDRSDRC_LPR);
+
+ if ((mdr & AT91_DDRSDRC_MD) == AT91_DDRSDRC_MD_LOW_POWER_DDR)
+ __raw_writel((mdr & ~AT91_DDRSDRC_MD) |
+ AT91_DDRSDRC_MD_DDR2, sdramc_base +
+ AT91_DDRSDRC_MDR);
+ __raw_writel((lpr & ~AT91_DDRSDRC_LPCB) |
+ AT91_DDRSDRC_LPCB_SELF_REFRESH, sdramc_base
+ + AT91_DDRSDRC_LPR);
+
+ if (sdramc_base1) {
+ mdr1 = __raw_readl(sdramc_base1 + AT91_DDRSDRC_MDR);
+ lpr1 = __raw_readl(sdramc_base1 + AT91_DDRSDRC_LPR);
+ if ((mdr1 & AT91_DDRSDRC_MD) == AT91_DDRSDRC_MD_LOW_POWER_DDR)
+ __raw_writel((mdr1 & ~AT91_DDRSDRC_MD) |
+ AT91_DDRSDRC_MD_DDR2,
+ sdramc_base1 +
+ AT91_DDRSDRC_MDR);
+ __raw_writel((lpr1 & ~AT91_DDRSDRC_LPCB) |
+ AT91_DDRSDRC_LPCB_SELF_REFRESH,
+ sdramc_base1 + AT91_DDRSDRC_LPR);
+ }
+ } else {
+ __raw_writel(mdr, sdramc_base + AT91_DDRSDRC_MDR);
+ __raw_writel(lpr, sdramc_base + AT91_DDRSDRC_LPR);
+ if (sdramc_base1) {
+ __raw_writel(mdr, sdramc_base1 + AT91_DDRSDRC_MDR);
+ __raw_writel(lpr, sdramc_base1 + AT91_DDRSDRC_LPR);
+ }
+ }
+ break;
+
+ case AT91_MEMCTRL_SDRAMC:
+ if (is_active) {
+ lpr = __raw_readl(sdramc_base + AT91_SDRAMC_LPR);
+
+ __raw_writel((lpr & ~AT91_SDRAMC_LPCB) |
+ AT91_SDRAMC_LPCB_SELF_REFRESH, sdramc_base
+ + AT91_SDRAMC_LPR);
+ } else {
+ __raw_writel(lpr, sdramc_base + AT91_SDRAMC_LPR);
+ }
+ break;
+ }
+}
+
+void atmel_pm_suspend(void __iomem *pmc, void __iomem *ramc0,
+ void __iomem *ramc1, int memctrl)
+{
+ int memtype, pm_mode;
+
+ memtype = memctrl & AT91_PM_MEMTYPE_MASK;
+ pm_mode = (memctrl >> AT91_PM_MODE_OFFSET) & AT91_PM_MODE_MASK;
+
+ dsb();
+
+ at91_sramc_self_refresh(1, memtype, ramc0, ramc1);
+
+#if defined(CONFIG_CPU_V7)
+ dsb();
+ wfi();
+#else
+ asm volatile ("mcr p15, 0, %0, c7, c0, 4" \
+ : : "r" (0) : "memory");
+#endif
+
+ at91_sramc_self_refresh(0, memtype, ramc0, ramc1);
+}
+EXPORT_PIE_SYMBOL(atmel_pm_suspend);
diff --git a/arch/arm/mach-at91/pm_suspend.S b/arch/arm/mach-at91/pm_suspend.S
deleted file mode 100644
index a25defda3d22..000000000000
--- a/arch/arm/mach-at91/pm_suspend.S
+++ /dev/null
@@ -1,338 +0,0 @@
-/*
- * arch/arm/mach-at91/pm_slow_clock.S
- *
- * Copyright (C) 2006 Savin Zlobec
- *
- * AT91SAM9 support:
- * Copyright (C) 2007 Anti Sullin <[email protected]
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- */
-#include <linux/linkage.h>
-#include <linux/clk/at91_pmc.h>
-#include "pm.h"
-
-#define SRAMC_SELF_FRESH_ACTIVE 0x01
-#define SRAMC_SELF_FRESH_EXIT 0x00
-
-pmc .req r0
-tmp1 .req r4
-tmp2 .req r5
-
-/*
- * Wait until master clock is ready (after switching master clock source)
- */
- .macro wait_mckrdy
-1: ldr tmp1, [pmc, #AT91_PMC_SR]
- tst tmp1, #AT91_PMC_MCKRDY
- beq 1b
- .endm
-
-/*
- * Wait until master oscillator has stabilized.
- */
- .macro wait_moscrdy
-1: ldr tmp1, [pmc, #AT91_PMC_SR]
- tst tmp1, #AT91_PMC_MOSCS
- beq 1b
- .endm
-
-/*
- * Wait until PLLA has locked.
- */
- .macro wait_pllalock
-1: ldr tmp1, [pmc, #AT91_PMC_SR]
- tst tmp1, #AT91_PMC_LOCKA
- beq 1b
- .endm
-
-/*
- * Put the processor to enter the idle state
- */
- .macro at91_cpu_idle
-
-#if defined(CONFIG_CPU_V7)
- mov tmp1, #AT91_PMC_PCK
- str tmp1, [pmc, #AT91_PMC_SCDR]
-
- dsb
-
- wfi @ Wait For Interrupt
-#else
- mcr p15, 0, tmp1, c7, c0, 4
-#endif
-
- .endm
-
- .text
-
- .arm
-
-/*
- * void at91_pm_suspend_in_sram(void __iomem *pmc, void __iomem *sdramc,
- * void __iomem *ramc1, int memctrl)
- * @input param:
- * @r0: base address of AT91_PMC
- * @r1: base address of SDRAM Controller (SDRAM, DDRSDR, or AT91_SYS)
- * @r2: base address of second SDRAM Controller or 0 if not present
- * @r3: pm information
- */
-/* at91_pm_suspend_in_sram must be 8-byte aligned per the requirements of fncpy() */
- .align 3
-ENTRY(at91_pm_suspend_in_sram)
- /* Save registers on stack */
- stmfd sp!, {r4 - r12, lr}
-
- /* Drain write buffer */
- mov tmp1, #0
- mcr p15, 0, tmp1, c7, c10, 4
-
- str r0, .pmc_base
- str r1, .sramc_base
- str r2, .sramc1_base
-
- and r0, r3, #AT91_PM_MEMTYPE_MASK
- str r0, .memtype
-
- lsr r0, r3, #AT91_PM_MODE_OFFSET
- and r0, r0, #AT91_PM_MODE_MASK
- str r0, .pm_mode
-
- /* Active the self-refresh mode */
- mov r0, #SRAMC_SELF_FRESH_ACTIVE
- bl at91_sramc_self_refresh
-
- ldr r0, .pm_mode
- tst r0, #AT91_PM_SLOW_CLOCK
- beq skip_disable_main_clock
-
- ldr pmc, .pmc_base
-
- /* Save Master clock setting */
- ldr tmp1, [pmc, #AT91_PMC_MCKR]
- str tmp1, .saved_mckr
-
- /*
- * Set the Master clock source to slow clock
- */
- bic tmp1, tmp1, #AT91_PMC_CSS
- str tmp1, [pmc, #AT91_PMC_MCKR]
-
- wait_mckrdy
-
- /* Save PLLA setting and disable it */
- ldr tmp1, [pmc, #AT91_CKGR_PLLAR]
- str tmp1, .saved_pllar
-
- mov tmp1, #AT91_PMC_PLLCOUNT
- orr tmp1, tmp1, #(1 << 29) /* bit 29 always set */
- str tmp1, [pmc, #AT91_CKGR_PLLAR]
-
- /* Turn off the main oscillator */
- ldr tmp1, [pmc, #AT91_CKGR_MOR]
- bic tmp1, tmp1, #AT91_PMC_MOSCEN
- orr tmp1, tmp1, #AT91_PMC_KEY
- str tmp1, [pmc, #AT91_CKGR_MOR]
-
-skip_disable_main_clock:
- ldr pmc, .pmc_base
-
- /* Wait for interrupt */
- at91_cpu_idle
-
- ldr r0, .pm_mode
- tst r0, #AT91_PM_SLOW_CLOCK
- beq skip_enable_main_clock
-
- ldr pmc, .pmc_base
-
- /* Turn on the main oscillator */
- ldr tmp1, [pmc, #AT91_CKGR_MOR]
- orr tmp1, tmp1, #AT91_PMC_MOSCEN
- orr tmp1, tmp1, #AT91_PMC_KEY
- str tmp1, [pmc, #AT91_CKGR_MOR]
-
- wait_moscrdy
-
- /* Restore PLLA setting */
- ldr tmp1, .saved_pllar
- str tmp1, [pmc, #AT91_CKGR_PLLAR]
-
- tst tmp1, #(AT91_PMC_MUL & 0xff0000)
- bne 3f
- tst tmp1, #(AT91_PMC_MUL & ~0xff0000)
- beq 4f
-3:
- wait_pllalock
-4:
-
- /*
- * Restore master clock setting
- */
- ldr tmp1, .saved_mckr
- str tmp1, [pmc, #AT91_PMC_MCKR]
-
- wait_mckrdy
-
-skip_enable_main_clock:
- /* Exit the self-refresh mode */
- mov r0, #SRAMC_SELF_FRESH_EXIT
- bl at91_sramc_self_refresh
-
- /* Restore registers, and return */
- ldmfd sp!, {r4 - r12, pc}
-ENDPROC(at91_pm_suspend_in_sram)
-
-/*
- * void at91_sramc_self_refresh(unsigned int is_active)
- *
- * @input param:
- * @r0: 1 - active self-refresh mode
- * 0 - exit self-refresh mode
- * register usage:
- * @r1: memory type
- * @r2: base address of the sram controller
- */
-
-ENTRY(at91_sramc_self_refresh)
- ldr r1, .memtype
- ldr r2, .sramc_base
-
- cmp r1, #AT91_MEMCTRL_MC
- bne ddrc_sf
-
- /*
- * at91rm9200 Memory controller
- */
-
- /*
- * For exiting the self-refresh mode, do nothing,
- * automatically exit the self-refresh mode.
- */
- tst r0, #SRAMC_SELF_FRESH_ACTIVE
- beq exit_sramc_sf
-
- /* Active SDRAM self-refresh mode */
- mov r3, #1
- str r3, [r2, #AT91_MC_SDRAMC_SRR]
- b exit_sramc_sf
-
-ddrc_sf:
- cmp r1, #AT91_MEMCTRL_DDRSDR
- bne sdramc_sf
-
- /*
- * DDR Memory controller
- */
- tst r0, #SRAMC_SELF_FRESH_ACTIVE
- beq ddrc_exit_sf
-
- /* LPDDR1 --> force DDR2 mode during self-refresh */
- ldr r3, [r2, #AT91_DDRSDRC_MDR]
- str r3, .saved_sam9_mdr
- bic r3, r3, #~AT91_DDRSDRC_MD
- cmp r3, #AT91_DDRSDRC_MD_LOW_POWER_DDR
- ldreq r3, [r2, #AT91_DDRSDRC_MDR]
- biceq r3, r3, #AT91_DDRSDRC_MD
- orreq r3, r3, #AT91_DDRSDRC_MD_DDR2
- streq r3, [r2, #AT91_DDRSDRC_MDR]
-
- /* Active DDRC self-refresh mode */
- ldr r3, [r2, #AT91_DDRSDRC_LPR]
- str r3, .saved_sam9_lpr
- bic r3, r3, #AT91_DDRSDRC_LPCB
- orr r3, r3, #AT91_DDRSDRC_LPCB_SELF_REFRESH
- str r3, [r2, #AT91_DDRSDRC_LPR]
-
- /* If using the 2nd ddr controller */
- ldr r2, .sramc1_base
- cmp r2, #0
- beq no_2nd_ddrc
-
- ldr r3, [r2, #AT91_DDRSDRC_MDR]
- str r3, .saved_sam9_mdr1
- bic r3, r3, #~AT91_DDRSDRC_MD
- cmp r3, #AT91_DDRSDRC_MD_LOW_POWER_DDR
- ldreq r3, [r2, #AT91_DDRSDRC_MDR]
- biceq r3, r3, #AT91_DDRSDRC_MD
- orreq r3, r3, #AT91_DDRSDRC_MD_DDR2
- streq r3, [r2, #AT91_DDRSDRC_MDR]
-
- /* Active DDRC self-refresh mode */
- ldr r3, [r2, #AT91_DDRSDRC_LPR]
- str r3, .saved_sam9_lpr1
- bic r3, r3, #AT91_DDRSDRC_LPCB
- orr r3, r3, #AT91_DDRSDRC_LPCB_SELF_REFRESH
- str r3, [r2, #AT91_DDRSDRC_LPR]
-
-no_2nd_ddrc:
- b exit_sramc_sf
-
-ddrc_exit_sf:
- /* Restore MDR in case of LPDDR1 */
- ldr r3, .saved_sam9_mdr
- str r3, [r2, #AT91_DDRSDRC_MDR]
- /* Restore LPR on AT91 with DDRAM */
- ldr r3, .saved_sam9_lpr
- str r3, [r2, #AT91_DDRSDRC_LPR]
-
- /* If using the 2nd ddr controller */
- ldr r2, .sramc1_base
- cmp r2, #0
- ldrne r3, .saved_sam9_mdr1
- strne r3, [r2, #AT91_DDRSDRC_MDR]
- ldrne r3, .saved_sam9_lpr1
- strne r3, [r2, #AT91_DDRSDRC_LPR]
-
- b exit_sramc_sf
-
- /*
- * SDRAMC Memory controller
- */
-sdramc_sf:
- tst r0, #SRAMC_SELF_FRESH_ACTIVE
- beq sdramc_exit_sf
-
- /* Active SDRAMC self-refresh mode */
- ldr r3, [r2, #AT91_SDRAMC_LPR]
- str r3, .saved_sam9_lpr
- bic r3, r3, #AT91_SDRAMC_LPCB
- orr r3, r3, #AT91_SDRAMC_LPCB_SELF_REFRESH
- str r3, [r2, #AT91_SDRAMC_LPR]
-
-sdramc_exit_sf:
- ldr r3, .saved_sam9_lpr
- str r3, [r2, #AT91_SDRAMC_LPR]
-
-exit_sramc_sf:
- mov pc, lr
-ENDPROC(at91_sramc_self_refresh)
-
-.pmc_base:
- .word 0
-.sramc_base:
- .word 0
-.sramc1_base:
- .word 0
-.memtype:
- .word 0
-.pm_mode:
- .word 0
-.saved_mckr:
- .word 0
-.saved_pllar:
- .word 0
-.saved_sam9_lpr:
- .word 0
-.saved_sam9_lpr1:
- .word 0
-.saved_sam9_mdr:
- .word 0
-.saved_sam9_mdr1:
- .word 0
-
-ENTRY(at91_pm_suspend_in_sram_sz)
- .word .-at91_pm_suspend_in_sram
--
2.8.0.rc3

2016-04-03 12:18:10

On Sat, Apr 23, 2016 at 01:15:03AM +0200, Alexandre Belloni wrote:
> Well, do you want me to iterate and use fncpy on all the functions from
> the generated binary?

No, because that will break the image too.

> I'm not sure this is necessary as the generated binary is self contained
> and doing so will force me to also ensure the offsets are kept the same.
> Doing only one copy is much more convenient. However, I still need to
> ensure the destination address is properly 8-byte aligned and the
> flush_icache_range().

What you need to do is to immitate being an ELF loader - in other words,
copy the blob according to the alignment rules of the blob (which may be
greater than 8-byte alignment) and use the symbol table to find the
functions and the type of the function (ARM vs ELF).

> I understand this is abusing fncpy() but it does want I need (still, I'm
> planning to avoid the BUG() by always passing a properly aligned
> destination address).

Yea yea yea, such arguments don't wash with me, sorry. The "but it does
what I need" is total bollocks, sorry. fncpy() is designed for a
purpose, and what you're doing is an abuse of it, one which I will not
stand for for the sake of long term maintainability.

--
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