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[PARISC] Use FIXUP_BRANCH_CLOBBER to asm clobber list

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Joel Soete noticed correctly that the fixup's clobbers must be listed
as the ASM clobbers. FIXUP_BRANCH in unaligned.c has a new macro which
lists all the clobbers in the fixup, we use this throughout the file
to simplify the process of listing clobbers in the future.

A missing "r1" clobber is added to our uaccess.h for the 64-bit
__put_kernel_asm. Interestingly this is a pretty serious bug since gcc
generates pretty good use of r1 as a temporary and the uses of
__put_kernel_asm are varied and dangerous if r1 is scratched during
an invalid write.

Signed-off-by: Joel Soete <soete.joel@tiscali.be>
Signed-off-by: Carlos O'Donell <carlos@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
This commit is contained in:
Carlos O'Donell 2006-04-22 14:47:21 -06:00 committed by Kyle McMartin
parent c8224e0074
commit 3fd3a74f45
2 changed files with 17 additions and 10 deletions
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18
arch/parisc/kernel/unaligned.c
View File

@ -43,6 +43,8 @@
"\tldil L%%" #lbl ", %%r1\n" \
"\tldo R%%" #lbl "(%%r1), %%r1\n" \
"\tbv,n %%r0(%%r1)\n"
/* If you use FIXUP_BRANCH, then you must list this clobber */
#define FIXUP_BRANCH_CLOBBER "r1"
/* 1111 1100 0000 0000 0001 0011 1100 0000 */
#define OPCODE1(a,b,c) ((a)<<26|(b)<<12|(c)<<6)
@ -157,7 +159,7 @@ static int emulate_ldh(struct pt_regs *regs, int toreg)
" .previous\n"
: "=r" (val), "=r" (ret)
: "0" (val), "r" (saddr), "r" (regs->isr)
: "r20" );
: "r20", FIXUP_BRANCH_CLOBBER );
DPRINTF("val = 0x" RFMT "\n", val);
@ -202,7 +204,7 @@ static int emulate_ldw(struct pt_regs *regs, int toreg, int flop)
" .previous\n"
: "=r" (val), "=r" (ret)
: "0" (val), "r" (saddr), "r" (regs->isr)
: "r19", "r20" );
: "r19", "r20", FIXUP_BRANCH_CLOBBER );
DPRINTF("val = 0x" RFMT "\n", val);
@ -253,7 +255,7 @@ static int emulate_ldd(struct pt_regs *regs, int toreg, int flop)
" .previous\n"
: "=r" (val), "=r" (ret)
: "0" (val), "r" (saddr), "r" (regs->isr)
: "r19", "r20" );
: "r19", "r20", FIXUP_BRANCH_CLOBBER );
#else
{
unsigned long valh=0,vall=0;
@ -287,7 +289,7 @@ static int emulate_ldd(struct pt_regs *regs, int toreg, int flop)
" .previous\n"
: "=r" (valh), "=r" (vall), "=r" (ret)
: "0" (valh), "1" (vall), "r" (saddr), "r" (regs->isr)
: "r19", "r20" );
: "r19", "r20", FIXUP_BRANCH_CLOBBER );
val=((__u64)valh<<32)|(__u64)vall;
}
#endif
@ -335,7 +337,7 @@ static int emulate_sth(struct pt_regs *regs, int frreg)
" .previous\n"
: "=r" (ret)
: "r" (val), "r" (regs->ior), "r" (regs->isr)
: "r19" );
: "r19", FIXUP_BRANCH_CLOBBER );
return ret;
}
@ -389,7 +391,7 @@ static int emulate_stw(struct pt_regs *regs, int frreg, int flop)
" .previous\n"
: "=r" (ret)
: "r" (val), "r" (regs->ior), "r" (regs->isr)
: "r19", "r20", "r21", "r22", "r1" );
: "r19", "r20", "r21", "r22", "r1", FIXUP_BRANCH_CLOBBER );
return 0;
}
@ -450,7 +452,7 @@ static int emulate_std(struct pt_regs *regs, int frreg, int flop)
" .previous\n"
: "=r" (ret)
: "r" (val), "r" (regs->ior), "r" (regs->isr)
: "r19", "r20", "r21", "r22", "r1" );
: "r19", "r20", "r21", "r22", "r1", FIXUP_BRANCH_CLOBBER );
#else
{
unsigned long valh=(val>>32),vall=(val&0xffffffffl);
@ -495,7 +497,7 @@ static int emulate_std(struct pt_regs *regs, int frreg, int flop)
" .previous\n"
: "=r" (ret)
: "r" (valh), "r" (vall), "r" (regs->ior), "r" (regs->isr)
: "r19", "r20", "r21", "r1" );
: "r19", "r20", "r21", "r1", FIXUP_BRANCH_CLOBBER );
}
#endif

9
include/asm-parisc/uaccess.h
View File

@ -172,7 +172,11 @@ struct exception_data {
/*
* The "__put_user/kernel_asm()" macros tell gcc they read from memory
* instead of writing. This is because they do not write to any memory
* gcc knows about, so there are no aliasing issues.
* gcc knows about, so there are no aliasing issues. These macros must
* also be aware that "fixup_put_user_skip_[12]" are executed in the
* context of the fault, and any registers used there must be listed
* as clobbers. In this case only "r1" is used by the current routines.
* r8/r9 are already listed as err/val.
*/
#ifdef __LP64__
@ -183,7 +187,8 @@ struct exception_data {
"\t.dword\t1b,fixup_put_user_skip_1\n" \
"\t.previous" \
: "=r"(__pu_err) \
: "r"(ptr), "r"(x), "0"(__pu_err))
: "r"(ptr), "r"(x), "0"(__pu_err) \
: "r1")
#define __put_user_asm(stx,x,ptr) \
__asm__ __volatile__ ( \