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Subject[PATCH v3 1/2] ARM: Pass IFSR register to do_PrefetchAbort()
Date
It needed for proper prefetch abort handling on ARMv7.

Instruction fault status register (IFSR) was introduced on ARMv7.
For older CPU we simulate IFSR with translation fault status. It
allows to generalize code.

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
---
arch/arm/include/asm/glue.h | 10 ++++++++--
arch/arm/kernel/entry-armv.S | 14 ++++----------
arch/arm/kernel/entry-common.S | 8 ++++++--
arch/arm/mm/fault.c | 2 +-
4 files changed, 19 insertions(+), 15 deletions(-)

diff --git a/arch/arm/include/asm/glue.h b/arch/arm/include/asm/glue.h
index a0e39d5..5bfaf6f 100644
--- a/arch/arm/include/asm/glue.h
+++ b/arch/arm/include/asm/glue.h
@@ -130,7 +130,10 @@
# ifdef CPU_PABORT_HANDLER
# define MULTI_PABORT 1
# else
-# define CPU_PABORT_HANDLER(reg, insn) mrc p15, 0, reg, cr6, cr0, 2
+# define CPU_PABORT_HANDLER(addr, ifsr, insn) \
+ mrc p15, 0, addr, c6, c0, 2 ; \
+ mrc p15, 0, ifsr, c5, c0, 1
+
# endif
#endif

@@ -138,7 +141,10 @@
# ifdef CPU_PABORT_HANDLER
# define MULTI_PABORT 1
# else
-# define CPU_PABORT_HANDLER(reg, insn) mov reg, insn
+#define __hash_5 #5
+# define CPU_PABORT_HANDLER(addr, ifsr, insn) \
+ mov addr, insn ; \
+ mov ifsr, __hash_5
# endif
#endif

diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index 3d727a8..335ae58 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -303,22 +303,16 @@ __pabt_svc:
tst r3, #PSR_I_BIT
biceq r9, r9, #PSR_I_BIT

- @
- @ set args, then call main handler
- @
- @ r0 - address of faulting instruction
- @ r1 - pointer to registers on stack
- @
#ifdef MULTI_PABORT
mov r0, r2 @ pass address of aborted instruction.
ldr r4, .LCprocfns
mov lr, pc
ldr pc, [r4, #PROCESSOR_PABT_FUNC]
#else
- CPU_PABORT_HANDLER(r0, r2)
+ CPU_PABORT_HANDLER(r0, r1, r2)
#endif
msr cpsr_c, r9 @ Maybe enable interrupts
- mov r1, sp @ regs
+ mov r2, sp @ regs
bl do_PrefetchAbort @ call abort handler

@
@@ -697,10 +691,10 @@ __pabt_usr:
mov lr, pc
ldr pc, [r4, #PROCESSOR_PABT_FUNC]
#else
- CPU_PABORT_HANDLER(r0, r2)
+ CPU_PABORT_HANDLER(r0, r1, r2)
#endif
enable_irq @ Enable interrupts
- mov r1, sp @ regs
+ mov r2, sp @ regs
bl do_PrefetchAbort @ call abort handler
UNWIND(.fnend )
/* fall through */
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 807cfeb..931ab9a 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -426,10 +426,14 @@ sys_mmap2:
ENDPROC(sys_mmap2)

ENTRY(pabort_ifar)
- mrc p15, 0, r0, cr6, cr0, 2
-ENTRY(pabort_noifar)
+ mrc p15, 0, r0, c6, c0, 2 @ get IFAR
+ mrc p15, 0, r1, c5, c0, 1 @ get IFSR
mov pc, lr
ENDPROC(pabort_ifar)
+ENTRY(pabort_noifar)
+ /* simulate IFSR with section translation fault status */
+ mov r1, #5
+ mov pc, lr
ENDPROC(pabort_noifar)

#ifdef CONFIG_OABI_COMPAT
diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index cc8829d..5e27462 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -506,7 +506,7 @@ do_DataAbort(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
}

asmlinkage void __exception
-do_PrefetchAbort(unsigned long addr, struct pt_regs *regs)
+do_PrefetchAbort(unsigned long addr, int ifsr, struct pt_regs *regs)
{
do_translation_fault(addr, 0, regs);
}
--
1.6.4.4


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