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Message-ID: <787b0d920609140134j5935c743kae4af8d51eea2a90@mail.gmail.com>
Date: Thu, 14 Sep 2006 04:34:00 -0400
From: "Albert Cahalan" <acahalan@...il.com>
To: linux-kernel@...r.kernel.org, "Andrew Morton" <akpm@...l.org>,
"Andi Kleen" <ak@...e.de>, "Linus Torvalds" <torvalds@...l.org>,
hpa@...or.com
Subject: [PATCH] i386/x86_64 signal handler arg fixes
Some time ago, the i386 kernel was patched to support user code that
has signal handlers marked with __attribute__((regparm(3))) or compiled
with the -mregparm=3 gcc option. This is useful for klibc at least.
The code wasn't quite right, and it never got ported to x86_64.
For i386, the non-RT frame is wrong. It was using the raw sig value
instead of the translated value, and did not pass the semi-documented
extra parameters.
For x86-64, the regparm 3 calling convention was simply missing.
This patch should do the job, provided I'm right in guessing that a
struct passed by value is really passed as a pointer in this case.
(the non-RT signal handler's second arg is a pass-by-value struct)
Signed-off-by: Albert Cahalan <acahalan@...il.com>
---
I'm sending this inline for review, and attached because
the whitespace will surely be mangled.
diff -Naurd old/arch/i386/kernel/signal.c new/arch/i386/kernel/signal.c
--- old/arch/i386/kernel/signal.c 2006-09-14 03:49:30.000000000 -0400
+++ new/arch/i386/kernel/signal.c 2006-09-14 03:52:54.000000000 -0400
@@ -375,9 +375,9 @@
/* Set up registers for signal handler */
regs->esp = (unsigned long) frame;
regs->eip = (unsigned long) ka->sa.sa_handler;
- regs->eax = (unsigned long) sig;
- regs->edx = (unsigned long) 0;
- regs->ecx = (unsigned long) 0;
+ regs->eax = (unsigned long) usig;
+ regs->edx = (unsigned long) &frame->sc;
+ regs->ecx = (unsigned long) &frame->fpstate;
set_fs(USER_DS);
regs->xds = __USER_DS;
diff -Naurd old/arch/x86_64/ia32/ia32_signal.c
new/arch/x86_64/ia32/ia32_signal.c
--- old/arch/x86_64/ia32/ia32_signal.c 2006-09-14 03:21:21.000000000 -0400
+++ new/arch/x86_64/ia32/ia32_signal.c 2006-09-14 03:47:32.000000000 -0400
@@ -433,6 +433,7 @@
{
struct sigframe __user *frame;
int err = 0;
+ int usig;
frame = get_sigframe(ka, regs, sizeof(*frame));
@@ -441,12 +442,10 @@
{
struct exec_domain *ed = current_thread_info()->exec_domain;
- err |= __put_user((ed
- && ed->signal_invmap
- && sig < 32
- ? ed->signal_invmap[sig]
- : sig),
- &frame->sig);
+ usig = ed && ed->signal_invmap && sig < 32
+ ? ed->signal_invmap[sig]
+ : sig;
+ err |= __put_user(usig,&frame->sig);
}
if (err)
goto give_sigsegv;
@@ -493,6 +492,9 @@
/* Set up registers for signal handler */
regs->rsp = (unsigned long) frame;
regs->rip = (unsigned long) ka->sa.sa_handler;
+ regs->rax = (unsigned long) usig;
+ regs->rdx = (unsigned long) &frame->sc;
+ regs->rcx = (unsigned long) &frame->fpstate;
asm volatile("movl %0,%%ds" :: "r" (__USER32_DS));
asm volatile("movl %0,%%es" :: "r" (__USER32_DS));
@@ -522,6 +524,7 @@
{
struct rt_sigframe __user *frame;
int err = 0;
+ int usig;
frame = get_sigframe(ka, regs, sizeof(*frame));
@@ -530,12 +533,10 @@
{
struct exec_domain *ed = current_thread_info()->exec_domain;
- err |= __put_user((ed
- && ed->signal_invmap
- && sig < 32
- ? ed->signal_invmap[sig]
- : sig),
- &frame->sig);
+ usig = ed && ed->signal_invmap && sig < 32
+ ? ed->signal_invmap[sig]
+ : sig;
+ err |= __put_user(usig,&frame->sig);
}
err |= __put_user(ptr_to_compat(&frame->info), &frame->pinfo);
err |= __put_user(ptr_to_compat(&frame->uc), &frame->puc);
@@ -589,6 +590,9 @@
/* Set up registers for signal handler */
regs->rsp = (unsigned long) frame;
regs->rip = (unsigned long) ka->sa.sa_handler;
+ regs->rax = (unsigned long) usig;
+ regs->rdx = (unsigned long) &frame->info;
+ regs->rcx = (unsigned long) &frame->uc;
asm volatile("movl %0,%%ds" :: "r" (__USER32_DS));
asm volatile("movl %0,%%es" :: "r" (__USER32_DS));
View attachment "regparm3.patch" of type "text/x-patch" (2838 bytes)
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