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xtensa: save and restore scompare1 SR on kernel entry

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Although scompare1 may be saved/restored by xchal_ncp_{load,store}
macros, explicit save/restore of registers manipulated by the kernel
itself is considered more correct.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>
This commit is contained in:
Max Filippov 2012-11-15 06:25:48 +04:00 committed by Chris Zankel
parent 2f6ea6a767
commit 733536b865
3 changed files with 15 additions and 1 deletions
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2
arch/xtensa/include/asm/ptrace.h
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@ -37,7 +37,7 @@ struct pt_regs {
unsigned long windowstart; /* 52 */
unsigned long syscall; /* 56 */
unsigned long icountlevel; /* 60 */
int reserved[1]; /* 64 */
unsigned long scompare1; /* 64 */
/* Additional configurable registers that are used by the compiler. */
xtregs_opt_t xtregs_opt;

1
arch/xtensa/kernel/asm-offsets.c
View file

@ -41,6 +41,7 @@ int main(void)
DEFINE(PT_SAR, offsetof (struct pt_regs, sar));
DEFINE(PT_ICOUNTLEVEL, offsetof (struct pt_regs, icountlevel));
DEFINE(PT_SYSCALL, offsetof (struct pt_regs, syscall));
DEFINE(PT_SCOMPARE1, offsetof(struct pt_regs, scompare1));
DEFINE(PT_AREG, offsetof (struct pt_regs, areg[0]));
DEFINE(PT_AREG0, offsetof (struct pt_regs, areg[0]));
DEFINE(PT_AREG1, offsetof (struct pt_regs, areg[1]));

13
arch/xtensa/kernel/entry.S
View file

@ -372,6 +372,13 @@ common_exception:
s32i a2, a1, PT_LBEG
s32i a3, a1, PT_LEND
/* Save SCOMPARE1 */
#if XCHAL_HAVE_S32C1I
rsr a2, scompare1
s32i a2, a1, PT_SCOMPARE1
#endif
/* Save optional registers. */
save_xtregs_opt a1 a2 a4 a5 a6 a7 PT_XTREGS_OPT
@ -433,6 +440,12 @@ common_exception_return:
load_xtregs_opt a1 a2 a4 a5 a6 a7 PT_XTREGS_OPT
/* Restore SCOMPARE1 */
#if XCHAL_HAVE_S32C1I
l32i a2, a1, PT_SCOMPARE1
wsr a2, scompare1
#endif
wsr a3, ps /* disable interrupts */
_bbci.l a3, PS_UM_BIT, kernel_exception_exit