2010-02-22 22:57:23

by Suresh Siddha

Subject: [patch 2/3] x86, ptrace: simplify xstateregs_get()

48 bytes (bytes 464..511) of the xstateregs payload come from the
kernel defined structure (xstate_fx_sw_bytes). Rest comes from the
xstate regs structure in the thread struct. Instead of having multiple
user_regset_copyout()'s, simplify the xstateregs_get() by first
copying the SW bytes into the xstate regs structure in the thread structure
and then using one user_regset_copyout() to copyout the xstateregs.

Requested-by: Roland McGrath <[email protected]>
Signed-off-by: Suresh Siddha <[email protected]>
---
arch/x86/kernel/i387.c | 30 +++++++-----------------------
1 file changed, 7 insertions(+), 23 deletions(-)

Index: tip/arch/x86/kernel/i387.c
===================================================================
--- tip.orig/arch/x86/kernel/i387.c
+++ tip/arch/x86/kernel/i387.c
@@ -243,34 +243,18 @@ int xstateregs_get(struct task_struct *t
return ret;

/*
- * First copy the fxsave bytes 0..463.
+ * Copy the 48bytes defined by the software first into the xstate
+ * memory layout in the thread struct, so that we can copy the entire
+ * xstateregs to the user using one user_regset_copyout().
*/
- ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
- &target->thread.xstate->xsave, 0,
- offsetof(struct user_xstateregs,
- i387.xstate_fx_sw));
- if (ret)
- return ret;
-
- /*
- * Copy the 48bytes defined by software.
- */
- ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
- xstate_fx_sw_bytes,
- offsetof(struct user_xstateregs,
- i387.xstate_fx_sw),
- offsetof(struct user_xstateregs,
- xsave_hdr));
- if (ret)
- return ret;
+ memcpy(&target->thread.xstate->fxsave.sw_reserved,
+ xstate_fx_sw_bytes, sizeof(xstate_fx_sw_bytes));

/*
- * Copy the rest of xstate memory layout.
+ * Copy the xstate memory layout.
*/
ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
- &target->thread.xstate->xsave.xsave_hdr,
- offsetof(struct user_xstateregs,
- xsave_hdr), -1);
+ &target->thread.xstate->xsave, 0, -1);
return ret;
}

2010-02-23 20:38:56

by Roland McGrath

Subject: Re: [patch 2/3] x86, ptrace: simplify xstateregs_get()

Acked-by: Roland McGrath <[email protected]>

2010-02-23 21:49:29

by Suresh Siddha

Subject: [tip:x86/ptrace] x86, ptrace: Simplify xstateregs_get()

Commit-ID: ff7fbc72e0c3ef7e94a27a3a918fd09ec9a30204
Gitweb: http://git.kernel.org/tip/ff7fbc72e0c3ef7e94a27a3a918fd09ec9a30204
Author: Suresh Siddha <[email protected]>
AuthorDate: Mon, 22 Feb 2010 14:51:33 -0800
Committer: H. Peter Anvin <[email protected]>
CommitDate: Tue, 23 Feb 2010 13:45:27 -0800

x86, ptrace: Simplify xstateregs_get()

48 bytes (bytes 464..511) of the xstateregs payload come from the
kernel defined structure (xstate_fx_sw_bytes). Rest comes from the
xstate regs structure in the thread struct. Instead of having multiple
user_regset_copyout()'s, simplify the xstateregs_get() by first
copying the SW bytes into the xstate regs structure in the thread structure
and then using one user_regset_copyout() to copyout the xstateregs.

Requested-by: Roland McGrath <[email protected]>
Signed-off-by: Suresh Siddha <[email protected]>
LKML-Reference: <[email protected]>
Acked-by: Roland McGrath <[email protected]>
Signed-off-by: H. Peter Anvin <[email protected]>
Cc: Oleg Nesterov <[email protected]>
---
arch/x86/kernel/i387.c | 30 +++++++-----------------------
1 files changed, 7 insertions(+), 23 deletions(-)

diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index 7a8a193..81e23bf 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -243,34 +243,18 @@ int xstateregs_get(struct task_struct *target, const struct user_regset *regset,
return ret;

/*
- * First copy the fxsave bytes 0..463.
+ * Copy the 48bytes defined by the software first into the xstate
+ * memory layout in the thread struct, so that we can copy the entire
+ * xstateregs to the user using one user_regset_copyout().
*/
- ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
- &target->thread.xstate->xsave, 0,
- offsetof(struct user_xstateregs,
- i387.xstate_fx_sw));
- if (ret)
- return ret;
-
- /*
- * Copy the 48bytes defined by software.
- */
- ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
- xstate_fx_sw_bytes,
- offsetof(struct user_xstateregs,
- i387.xstate_fx_sw),
- offsetof(struct user_xstateregs,
- xsave_hdr));
- if (ret)
- return ret;
+ memcpy(&target->thread.xstate->fxsave.sw_reserved,
+ xstate_fx_sw_bytes, sizeof(xstate_fx_sw_bytes));

/*
- * Copy the rest of xstate memory layout.
+ * Copy the xstate memory layout.
*/
ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
- &target->thread.xstate->xsave.xsave_hdr,
- offsetof(struct user_xstateregs,
- xsave_hdr), -1);
+ &target->thread.xstate->xsave, 0, -1);
return ret;
}