Maxim Kuvyrkov wrote:
The following patch define sigcontext ABI of ColdFire.
...
--- a/arch/m68k/kernel/signal.c
+++ b/arch/m68k/kernel/signal.c
@@ -897,9 +897,15 @@ static void setup_rt_frame (int sig, struct k_sigaction *ka, siginfo_t *info,
/* Set up to return from userspace. */
err |= __put_user(frame->retcode, &frame->pretcode);
+#ifdef __mcoldfire__
+ /* move.w #,d0; trap #0 */
+ err |= __put_user(0x303c0000 + __NR_rt_sigreturn,
+ (long __user *)(frame->retcode + 0));
+#else
/* moveq #,d0; notb d0; trap #0 */
err |= __put_user(0x70004600 + ((__NR_rt_sigreturn ^ 0xff) << 16),
(long __user *)(frame->retcode + 0));
+#endif
err |= __put_user(0x4e40, (short __user *)(frame->retcode + 4));
if (err)
This turned out to be buggy: move.w will only set the lower 16 bits of
%d0 so if the signal handler leaves something in the high-order bits,
then the trampoline will trap into a non-existent syscall. The attached
patch fixes this; nothing else in it has changed since the initial revision.
I was lured into thinking that the above sequence is OK by m68knommu's
version of the trampoline. Arch/m68knommu/kernel/entry.S uses "move
#__NR_rt_sigreturn,%d0" which assembles into "move.w". This is too is
buggy and I'm also attaching the fix for the nommu version.
Regards,
--
Maxim K.
CodeSourcery
From bafb4e11ac13ea3095d9e8510f9a58c4cdc0481d Mon Sep 17 00:00:00 2001
From: Maxim Kuvyrkov <maxim@xxxxxxxxxxxxxxxx>
Date: Wed, 23 Sep 2009 01:22:43 +0400
Subject: [PATCH 1/2] Define sigcontext ABI of ColdFire
The following patch defines sigcontext ABI of ColdFire. Due to ISA
restrictions ColdFire needs different rt_sigreturn trampoline.
And due to ColdFire FP registers being 8-bytes instead of 12-bytes on
m68k, sigcontext and fpregset structures should be updated.
Regarding the sc_fpstate[16+6*8] field, it would've been enough 16
bytes to store ColdFire's FP state. To accomodate GLIBC's libSegFault
it would'be been enough 6*8 bytes (room for the 6 non-call-clobbered
FP registers). I set it to 16+6*8 to provide some extra space for any
future changes in the ColdFire FPU.
Signed-off-by: Maxim Kuvyrkov <maxim@xxxxxxxxxxxxxxxx>
---
arch/m68k/include/asm/sigcontext.h | 6 ++++++
arch/m68k/include/asm/ucontext.h | 4 ++++
arch/m68k/kernel/signal.c | 7 +++++++
3 files changed, 17 insertions(+), 0 deletions(-)
diff --git a/arch/m68k/include/asm/sigcontext.h b/arch/m68k/include/asm/sigcontext.h
index 523db2a..1320eaa 100644
--- a/arch/m68k/include/asm/sigcontext.h
+++ b/arch/m68k/include/asm/sigcontext.h
@@ -15,9 +15,15 @@ struct sigcontext {
unsigned long sc_pc;
unsigned short sc_formatvec;
#ifndef __uClinux__
+# ifdef __mcoldfire__
+ unsigned long sc_fpregs[2][2]; /* room for two fp registers */
+ unsigned long sc_fpcntl[3];
+ unsigned char sc_fpstate[16+6*8];
+# else
unsigned long sc_fpregs[2*3]; /* room for two fp registers */
unsigned long sc_fpcntl[3];
unsigned char sc_fpstate[216];
+# endif
#endif
};
diff --git a/arch/m68k/include/asm/ucontext.h b/arch/m68k/include/asm/ucontext.h
index e4e2266..00dcc51 100644
--- a/arch/m68k/include/asm/ucontext.h
+++ b/arch/m68k/include/asm/ucontext.h
@@ -7,7 +7,11 @@ typedef greg_t gregset_t[NGREG];
typedef struct fpregset {
int f_fpcntl[3];
+#ifdef __mcoldfire__
+ int f_fpregs[8][2];
+#else
int f_fpregs[8*3];
+#endif
} fpregset_t;
struct mcontext {
diff --git a/arch/m68k/kernel/signal.c b/arch/m68k/kernel/signal.c
index de2d05d..4b38753 100644
--- a/arch/m68k/kernel/signal.c
+++ b/arch/m68k/kernel/signal.c
@@ -897,10 +897,17 @@ static void setup_rt_frame (int sig, struct k_sigaction *ka, siginfo_t *info,
/* Set up to return from userspace. */
err |= __put_user(frame->retcode, &frame->pretcode);
+#ifdef __mcoldfire__
+ /* movel #__NR_rt_sigreturn,d0; trap #0 */
+ err |= __put_user(0x203c0000, (long __user *)(frame->retcode + 0));
+ err |= __put_user(0x00004e40 + (__NR_rt_sigreturn << 16),
+ (long __user *)(frame->retcode + 4));
+#else
/* moveq #,d0; notb d0; trap #0 */
err |= __put_user(0x70004600 + ((__NR_rt_sigreturn ^ 0xff) << 16),
(long __user *)(frame->retcode + 0));
err |= __put_user(0x4e40, (short __user *)(frame->retcode + 4));
+#endif
if (err)
goto give_sigsegv;
--
1.6.4
From ac003b05af17bb48e6acffd454cae6fdf6e80737 Mon Sep 17 00:00:00 2001
From: Maxim Kuvyrkov <maxim@xxxxxxxxxxxxxxxx>
Date: Wed, 23 Sep 2009 01:25:44 +0400
Subject: [PATCH 2/2] Fix m68k-uclinux's rt_sigreturn trampoline
Signed-off-by: Maxim Kuvyrkov <maxim@xxxxxxxxxxxxxxxx>
---
arch/m68knommu/kernel/entry.S | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/arch/m68knommu/kernel/entry.S b/arch/m68knommu/kernel/entry.S
index f56faa5..2717605 100644
--- a/arch/m68knommu/kernel/entry.S
+++ b/arch/m68knommu/kernel/entry.S
@@ -145,6 +145,6 @@ ENTRY(ret_from_user_signal)
trap #0
ENTRY(ret_from_user_rt_signal)
- move #__NR_rt_sigreturn,%d0
+ movel #__NR_rt_sigreturn,%d0
trap #0
--
1.6.4
