[Patch 1/3] PPC64-HWBKPT: Disable interrupts for data breakpoint exceptions
From: K.Prasad <hidden>
Date: 2010-05-12 03:32:15
Data address breakpoint exceptions are currently handled along with page-faults which require interrupts to remain in enabled state. Since exception handling for data breakpoints aren't pre-empt safe, we handle them separately. Signed-off-by: K.Prasad <redacted> Acked-by: Paul Mackerras <redacted> --- arch/powerpc/kernel/exceptions-64s.S | 13 ++++++++++++- arch/powerpc/mm/fault.c | 5 +++-- 2 files changed, 15 insertions(+), 3 deletions(-) Index: linux-2.6.ppc64_test/arch/powerpc/kernel/exceptions-64s.S ===================================================================
--- linux-2.6.ppc64_test.orig/arch/powerpc/kernel/exceptions-64s.S
+++ linux-2.6.ppc64_test/arch/powerpc/kernel/exceptions-64s.S@@ -735,8 +735,11 @@ _STATIC(do_hash_page) std r3,_DAR(r1) std r4,_DSISR(r1) - andis. r0,r4,0xa450 /* weird error? */ + andis. r0,r4,0xa410 /* weird error? */ bne- handle_page_fault /* if not, try to insert a HPTE */ + andis. r0,r4,DSISR_DABRMATCH@h + bne- handle_dabr_fault + BEGIN_FTR_SECTION andis. r0,r4,0x0020 /* Is it a segment table fault? */ bne- do_ste_alloc /* If so handle it */
@@ -823,6 +826,14 @@ END_FW_FTR_SECTION_IFCLR(FW_FEATURE_ISER bl .raw_local_irq_restore b 11f +/* We have a data breakpoint exception - handle it */ +handle_dabr_fault: + ld r4,_DAR(r1) + ld r5,_DSISR(r1) + addi r3,r1,STACK_FRAME_OVERHEAD + bl .do_dabr + b .ret_from_except_lite + /* Here we have a page fault that hash_page can't handle. */ handle_page_fault: ENABLE_INTS
Index: linux-2.6.ppc64_test/arch/powerpc/mm/fault.c ===================================================================
--- linux-2.6.ppc64_test.orig/arch/powerpc/mm/fault.c
+++ linux-2.6.ppc64_test/arch/powerpc/mm/fault.c@@ -151,13 +151,14 @@ int __kprobes do_page_fault(struct pt_re if (!user_mode(regs) && (address >= TASK_SIZE)) return SIGSEGV; -#if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE)) +#if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE) || \ + defined(CONFIG_PPC_BOOK3S_64)) if (error_code & DSISR_DABRMATCH) { /* DABR match */ do_dabr(regs, address, error_code); return 0; } -#endif /* !(CONFIG_4xx || CONFIG_BOOKE)*/ +#endif if (in_atomic() || mm == NULL) { if (!user_mode(regs))