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authorMichael Neuling <mikey@neuling.org>2008-10-23 00:42:36 +0000
committerPaul Mackerras <paulus@samba.org>2008-10-31 16:12:00 +1100
commit16c29d180becc5bdf92fd0fc7314a44a671b5f4e (patch)
treecf8ed40be5a456dd6b61eda6d339cd4b8341f655 /arch/powerpc/kernel/signal_32.c
parentb160544cccb403310cf38ddb3ebc156ea454848a (diff)
powerpc: Fix swapcontext system for VSX + old ucontext size
Since VSX support was added, we now have two sizes of ucontext_t; the older, smaller size without the extra VSX state, and the new larger size with the extra VSX state. A program using the sys_swapcontext system call and supplying smaller ucontext_t structures will currently get an EINVAL error if the task has used VSX (e.g. because of calling library code that uses VSX) and the old_ctx argument is non-NULL (i.e. the program is asking for its current context to be saved). Thus the program will start getting EINVAL errors on calls that previously worked. This commit changes this behaviour so that we don't send an EINVAL in this case. It will now return the smaller context but the VSX MSR bit will always be cleared to indicate that the ucontext_t doesn't include the extra VSX state, even if the task has executed VSX instructions. Both 32 and 64 bit cases are updated. [paulus@samba.org - also fix some access_ok() and get_user() calls] Thanks to Ben Herrenschmidt for noticing this problem. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/kernel/signal_32.c')
-rw-r--r--arch/powerpc/kernel/signal_32.c36
1 files changed, 15 insertions, 21 deletions
diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index 3e80aa32b8b..a6a43103655 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -410,7 +410,7 @@ inline unsigned long copy_fpr_from_user(struct task_struct *task,
* altivec/spe instructions at some point.
*/
static int save_user_regs(struct pt_regs *regs, struct mcontext __user *frame,
- int sigret)
+ int sigret, int ctx_has_vsx_region)
{
unsigned long msr = regs->msr;
@@ -451,7 +451,7 @@ static int save_user_regs(struct pt_regs *regs, struct mcontext __user *frame,
* the saved MSR value to indicate that frame->mc_vregs
* contains valid data
*/
- if (current->thread.used_vsr) {
+ if (current->thread.used_vsr && ctx_has_vsx_region) {
__giveup_vsx(current);
if (copy_vsx_to_user(&frame->mc_vsregs, current))
return 1;
@@ -858,11 +858,11 @@ int handle_rt_signal32(unsigned long sig, struct k_sigaction *ka,
frame = &rt_sf->uc.uc_mcontext;
addr = frame;
if (vdso32_rt_sigtramp && current->mm->context.vdso_base) {
- if (save_user_regs(regs, frame, 0))
+ if (save_user_regs(regs, frame, 0, 1))
goto badframe;
regs->link = current->mm->context.vdso_base + vdso32_rt_sigtramp;
} else {
- if (save_user_regs(regs, frame, __NR_rt_sigreturn))
+ if (save_user_regs(regs, frame, __NR_rt_sigreturn, 1))
goto badframe;
regs->link = (unsigned long) frame->tramp;
}
@@ -936,12 +936,13 @@ long sys_swapcontext(struct ucontext __user *old_ctx,
int ctx_size, int r6, int r7, int r8, struct pt_regs *regs)
{
unsigned char tmp;
+ int ctx_has_vsx_region = 0;
#ifdef CONFIG_PPC64
unsigned long new_msr = 0;
if (new_ctx &&
- __get_user(new_msr, &new_ctx->uc_mcontext.mc_gregs[PT_MSR]))
+ get_user(new_msr, &new_ctx->uc_mcontext.mc_gregs[PT_MSR]))
return -EFAULT;
/*
* Check that the context is not smaller than the original
@@ -956,16 +957,9 @@ long sys_swapcontext(struct ucontext __user *old_ctx,
if ((ctx_size < sizeof(struct ucontext)) &&
(new_msr & MSR_VSX))
return -EINVAL;
-#ifdef CONFIG_VSX
- /*
- * If userspace doesn't provide enough room for VSX data,
- * but current thread has used VSX, we don't have anywhere
- * to store the full context back into.
- */
- if ((ctx_size < sizeof(struct ucontext)) &&
- (current->thread.used_vsr && old_ctx))
- return -EINVAL;
-#endif
+ /* Does the context have enough room to store VSX data? */
+ if (ctx_size >= sizeof(struct ucontext))
+ ctx_has_vsx_region = 1;
#else
/* Context size is for future use. Right now, we only make sure
* we are passed something we understand
@@ -985,17 +979,17 @@ long sys_swapcontext(struct ucontext __user *old_ctx,
*/
mctx = (struct mcontext __user *)
((unsigned long) &old_ctx->uc_mcontext & ~0xfUL);
- if (!access_ok(VERIFY_WRITE, old_ctx, sizeof(*old_ctx))
- || save_user_regs(regs, mctx, 0)
+ if (!access_ok(VERIFY_WRITE, old_ctx, ctx_size)
+ || save_user_regs(regs, mctx, 0, ctx_has_vsx_region)
|| put_sigset_t(&old_ctx->uc_sigmask, &current->blocked)
|| __put_user(to_user_ptr(mctx), &old_ctx->uc_regs))
return -EFAULT;
}
if (new_ctx == NULL)
return 0;
- if (!access_ok(VERIFY_READ, new_ctx, sizeof(*new_ctx))
+ if (!access_ok(VERIFY_READ, new_ctx, ctx_size)
|| __get_user(tmp, (u8 __user *) new_ctx)
- || __get_user(tmp, (u8 __user *) (new_ctx + 1) - 1))
+ || __get_user(tmp, (u8 __user *) new_ctx + ctx_size - 1))
return -EFAULT;
/*
@@ -1196,11 +1190,11 @@ int handle_signal32(unsigned long sig, struct k_sigaction *ka,
goto badframe;
if (vdso32_sigtramp && current->mm->context.vdso_base) {
- if (save_user_regs(regs, &frame->mctx, 0))
+ if (save_user_regs(regs, &frame->mctx, 0, 1))
goto badframe;
regs->link = current->mm->context.vdso_base + vdso32_sigtramp;
} else {
- if (save_user_regs(regs, &frame->mctx, __NR_sigreturn))
+ if (save_user_regs(regs, &frame->mctx, __NR_sigreturn, 1))
goto badframe;
regs->link = (unsigned long) frame->mctx.tramp;
}