[patch 07/10] watchdog: hpwdt: fix use of inline assembly

Greg KH
2008-06-23T23:09:27Z

[-- Attachment #1: watchdog-hpwdt-fix-use-of-inline-assembly.patch --]
[-- Type: text/plain, Size: 8115 bytes --]

2.6.25.9-stable review patch. If anyone has any objections, please let
us know.

------------------
From: Linus Torvalds <torvalds@linux-foundation.org>

commit 1f6ef2342972dc7fd623f360f84006e2304eb935 upstream

The inline assembly in drivers/watchdog/hpwdt.c was incredibly broken,
and included all the function prologue and epilogue stuff, even though
it was itself then inside a C function where the compiler would add its
own prologue and epilogue on top of it all.

This then just _happened_ to work if you had exactly the right compiler
version and exactly the right compiler flags, so that gcc just happened
to not create any prologue at all (the gcc-generated epilogue wouldn't
matter, since it would never be reached).

But the more proper way to fix it is to simply not do this. Move the
inline asm to the top level, with no surrounding function at all (the
better alternative would be to remove the prologue and make it actually
use proper description of the arguments to the inline asm, but that's a
bigger change than the one I'm willing to make right now).

Tested-by: S.Çağlar Onur <caglar@pardus.org.tr>
Acked-by: Thomas Mingarelli <Thomas.Mingarelli@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/watchdog/hpwdt.c | 154 ++++++++++++++++++++++++-----------------------
1 file changed, 79 insertions(+), 75 deletions(-)

--- a/drivers/watchdog/hpwdt.c
+++ b/drivers/watchdog/hpwdt.c
@@ -140,49 +140,52 @@ static struct pci_device_id hpwdt_device
};
MODULE_DEVICE_TABLE(pci, hpwdt_devices);

+extern asmlinkage void asminline_call(struct cmn_registers *pi86Regs, unsigned long *pRomEntry);
+
#ifndef CONFIG_X86_64
/* --32 Bit Bios------------------------------------------------------------ */

#define HPWDT_ARCH 32

-static void asminline_call(struct cmn_registers *pi86Regs,
- unsigned long *pRomEntry)
-{
- asm("pushl %ebp \n\t"
- "movl %esp, %ebp \n\t"
- "pusha \n\t"
- "pushf \n\t"
- "push %es \n\t"
- "push %ds \n\t"
- "pop %es \n\t"
- "movl 8(%ebp),%eax \n\t"
- "movl 4(%eax),%ebx \n\t"
- "movl 8(%eax),%ecx \n\t"
- "movl 12(%eax),%edx \n\t"
- "movl 16(%eax),%esi \n\t"
- "movl 20(%eax),%edi \n\t"
- "movl (%eax),%eax \n\t"
- "push %cs \n\t"
- "call *12(%ebp) \n\t"
- "pushf \n\t"
- "pushl %eax \n\t"
- "movl 8(%ebp),%eax \n\t"
- "movl %ebx,4(%eax) \n\t"
- "movl %ecx,8(%eax) \n\t"
- "movl %edx,12(%eax) \n\t"
- "movl %esi,16(%eax) \n\t"
- "movl %edi,20(%eax) \n\t"
- "movw %ds,24(%eax) \n\t"
- "movw %es,26(%eax) \n\t"
- "popl %ebx \n\t"
- "movl %ebx,(%eax) \n\t"
- "popl %ebx \n\t"
- "movl %ebx,28(%eax) \n\t"
- "pop %es \n\t"
- "popf \n\t"
- "popa \n\t"
- "leave \n\t" "ret");
-}
+asm(".text \n\t"
+ ".align 4 \n"
+ "asminline_call: \n\t"
+ "pushl %ebp \n\t"
+ "movl %esp, %ebp \n\t"
+ "pusha \n\t"
+ "pushf \n\t"
+ "push %es \n\t"
+ "push %ds \n\t"
+ "pop %es \n\t"
+ "movl 8(%ebp),%eax \n\t"
+ "movl 4(%eax),%ebx \n\t"
+ "movl 8(%eax),%ecx \n\t"
+ "movl 12(%eax),%edx \n\t"
+ "movl 16(%eax),%esi \n\t"
+ "movl 20(%eax),%edi \n\t"
+ "movl (%eax),%eax \n\t"
+ "push %cs \n\t"
+ "call *12(%ebp) \n\t"
+ "pushf \n\t"
+ "pushl %eax \n\t"
+ "movl 8(%ebp),%eax \n\t"
+ "movl %ebx,4(%eax) \n\t"
+ "movl %ecx,8(%eax) \n\t"
+ "movl %edx,12(%eax) \n\t"
+ "movl %esi,16(%eax) \n\t"
+ "movl %edi,20(%eax) \n\t"
+ "movw %ds,24(%eax) \n\t"
+ "movw %es,26(%eax) \n\t"
+ "popl %ebx \n\t"
+ "movl %ebx,(%eax) \n\t"
+ "popl %ebx \n\t"
+ "movl %ebx,28(%eax) \n\t"
+ "pop %es \n\t"
+ "popf \n\t"
+ "popa \n\t"
+ "leave \n\t"
+ "ret \n\t"
+ ".previous");

/*
* cru_detect
@@ -333,43 +336,44 @@ static int __devinit detect_cru_service(

#define HPWDT_ARCH 64

-static void asminline_call(struct cmn_registers *pi86Regs,
- unsigned long *pRomEntry)
-{
- asm("pushq %rbp \n\t"
- "movq %rsp, %rbp \n\t"
- "pushq %rax \n\t"
- "pushq %rbx \n\t"
- "pushq %rdx \n\t"
- "pushq %r12 \n\t"
- "pushq %r9 \n\t"
- "movq %rsi, %r12 \n\t"
- "movq %rdi, %r9 \n\t"
- "movl 4(%r9),%ebx \n\t"
- "movl 8(%r9),%ecx \n\t"
- "movl 12(%r9),%edx \n\t"
- "movl 16(%r9),%esi \n\t"
- "movl 20(%r9),%edi \n\t"
- "movl (%r9),%eax \n\t"
- "call *%r12 \n\t"
- "pushfq \n\t"
- "popq %r12 \n\t"
- "popfq \n\t"
- "movl %eax, (%r9) \n\t"
- "movl %ebx, 4(%r9) \n\t"
- "movl %ecx, 8(%r9) \n\t"
- "movl %edx, 12(%r9) \n\t"
- "movl %esi, 16(%r9) \n\t"
- "movl %edi, 20(%r9) \n\t"
- "movq %r12, %rax \n\t"
- "movl %eax, 28(%r9) \n\t"
- "popq %r9 \n\t"
- "popq %r12 \n\t"
- "popq %rdx \n\t"
- "popq %rbx \n\t"
- "popq %rax \n\t"
- "leave \n\t" "ret");
-}
+asm(".text \n\t"
+ ".align 4 \n"
+ "asminline_call: \n\t"
+ "pushq %rbp \n\t"
+ "movq %rsp, %rbp \n\t"
+ "pushq %rax \n\t"
+ "pushq %rbx \n\t"
+ "pushq %rdx \n\t"
+ "pushq %r12 \n\t"
+ "pushq %r9 \n\t"
+ "movq %rsi, %r12 \n\t"
+ "movq %rdi, %r9 \n\t"
+ "movl 4(%r9),%ebx \n\t"
+ "movl 8(%r9),%ecx \n\t"
+ "movl 12(%r9),%edx \n\t"
+ "movl 16(%r9),%esi \n\t"
+ "movl 20(%r9),%edi \n\t"
+ "movl (%r9),%eax \n\t"
+ "call *%r12 \n\t"
+ "pushfq \n\t"
+ "popq %r12 \n\t"
+ "popfq \n\t"
+ "movl %eax, (%r9) \n\t"
+ "movl %ebx, 4(%r9) \n\t"
+ "movl %ecx, 8(%r9) \n\t"
+ "movl %edx, 12(%r9) \n\t"
+ "movl %esi, 16(%r9) \n\t"
+ "movl %edi, 20(%r9) \n\t"
+ "movq %r12, %rax \n\t"
+ "movl %eax, 28(%r9) \n\t"
+ "popq %r9 \n\t"
+ "popq %r12 \n\t"
+ "popq %rdx \n\t"
+ "popq %rbx \n\t"
+ "popq %rax \n\t"
+ "leave \n\t"
+ "ret \n\t"
+ ".previous");

/*
* dmi_find_cru

--