*
* Low-level vector interface routines
*
- * Note: there is a StrongARM bug in the STMIA rn, {regs}^ instruction that causes
- * it to save wrong values... Be aware!
+ * Note: there is a StrongARM bug in the STMIA rn, {regs}^ instruction
+ * that causes it to save wrong values... Be aware!
*/
#include <asm/memory.h>
* Interrupt handling. Preserves r7, r8, r9
*/
.macro irq_handler
+ get_irqnr_preamble r5, lr
1: get_irqnr_and_base r0, r6, r5, lr
movne r1, sp
@
.endm
+#ifdef CONFIG_KPROBES
+ .section .kprobes.text,"ax",%progbits
+#else
+ .text
+#endif
+
/*
* Invalid mode handlers
*/
@ cpsr_<exception>, "old_r0"
mov r0, sp
- and r2, r6, #0x1f
b bad_mode
/*
#define SPFIX(code...)
#endif
- .macro svc_entry
- sub sp, sp, #S_FRAME_SIZE
+ .macro svc_entry, stack_hole=0
+ sub sp, sp, #(S_FRAME_SIZE + \stack_hole)
SPFIX( tst sp, #4 )
SPFIX( bicne sp, sp, #4 )
stmib sp, {r1 - r12}
ldmia r0, {r1 - r3}
add r5, sp, #S_SP @ here for interlock avoidance
mov r4, #-1 @ "" "" "" ""
- add r0, sp, #S_FRAME_SIZE @ "" "" "" ""
+ add r0, sp, #(S_FRAME_SIZE + \stack_hole)
SPFIX( addne r0, r0, #4 )
str r1, [sp] @ save the "real" r0 copied
@ from the exception stack
@ The abort handler must return the aborted address in r0, and
@ the fault status register in r1. r9 must be preserved.
@
-#ifdef MULTI_ABORT
+#ifdef MULTI_DABORT
ldr r4, .LCprocfns
mov lr, pc
- ldr pc, [r4]
+ ldr pc, [r4, #PROCESSOR_DABT_FUNC]
#else
- bl CPU_ABORT_HANDLER
+ bl CPU_DABORT_HANDLER
#endif
@
.align 5
__und_svc:
+#ifdef CONFIG_KPROBES
+ @ If a kprobe is about to simulate a "stmdb sp..." instruction,
+ @ it obviously needs free stack space which then will belong to
+ @ the saved context.
+ svc_entry 64
+#else
svc_entry
+#endif
@
@ call emulation code, which returns using r9 if it has emulated
mrs r9, cpsr
tst r3, #PSR_I_BIT
biceq r9, r9, #PSR_I_BIT
- msr cpsr_c, r9
@
@ set args, then call main handler
@ r0 - address of faulting instruction
@ r1 - pointer to registers on stack
@
- mov r0, r2 @ address (pc)
+#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)
+#endif
+ msr cpsr_c, r9 @ Maybe enable interrupts
mov r1, sp @ regs
bl do_PrefetchAbort @ call abort handler
.align 5
.LCcralign:
.word cr_alignment
-#ifdef MULTI_ABORT
+#ifdef MULTI_DABORT
.LCprocfns:
.word processor
#endif
str r1, [sp] @ save the "real" r0 copied
@ from the exception stack
-#if __LINUX_ARM_ARCH__ < 6 && !defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG)
-#ifndef CONFIG_MMU
-#warning "NPTL on non MMU needs fixing"
-#else
- @ make sure our user space atomic helper is aborted
- cmp r2, #TASK_SIZE
- bichs r3, r3, #PSR_Z_BIT
-#endif
-#endif
-
@
@ We are now ready to fill in the remaining blanks on the stack:
@
zero_fp
.endm
+ .macro kuser_cmpxchg_check
+#if __LINUX_ARM_ARCH__ < 6 && !defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG)
+#ifndef CONFIG_MMU
+#warning "NPTL on non MMU needs fixing"
+#else
+ @ Make sure our user space atomic helper is restarted
+ @ if it was interrupted in a critical region. Here we
+ @ perform a quick test inline since it should be false
+ @ 99.9999% of the time. The rest is done out of line.
+ cmp r2, #TASK_SIZE
+ blhs kuser_cmpxchg_fixup
+#endif
+#endif
+ .endm
+
.align 5
__dabt_usr:
usr_entry
+ kuser_cmpxchg_check
@
@ Call the processor-specific abort handler:
@ The abort handler must return the aborted address in r0, and
@ the fault status register in r1.
@
-#ifdef MULTI_ABORT
+#ifdef MULTI_DABORT
ldr r4, .LCprocfns
mov lr, pc
- ldr pc, [r4]
+ ldr pc, [r4, #PROCESSOR_DABT_FUNC]
#else
- bl CPU_ABORT_HANDLER
+ bl CPU_DABORT_HANDLER
#endif
@
.align 5
__irq_usr:
usr_entry
+ kuser_cmpxchg_check
#ifdef CONFIG_TRACE_IRQFLAGS
bl trace_hardirqs_off
@
@ r0 - instruction
@
-1: ldrt r0, [r4]
adr r9, ret_from_exception
adr lr, __und_usr_unknown
+1: ldrt r0, [r4]
@
@ fallthrough to call_fpe
@
* co-processor instructions. However, we have to watch out
* for the ARM6/ARM7 SWI bug.
*
+ * NEON is a special case that has to be handled here. Not all
+ * NEON instructions are co-processor instructions, so we have
+ * to make a special case of checking for them. Plus, there's
+ * five groups of them, so we have a table of mask/opcode pairs
+ * to check against, and if any match then we branch off into the
+ * NEON handler code.
+ *
* Emulators may wish to make use of the following registers:
* r0 = instruction opcode.
* r2 = PC+4
* lr = unrecognised instruction return address
*/
call_fpe:
+#ifdef CONFIG_NEON
+ adr r6, .LCneon_opcodes
+2:
+ ldr r7, [r6], #4 @ mask value
+ cmp r7, #0 @ end mask?
+ beq 1f
+ and r8, r0, r7
+ ldr r7, [r6], #4 @ opcode bits matching in mask
+ cmp r8, r7 @ NEON instruction?
+ bne 2b
+ get_thread_info r10
+ mov r7, #1
+ strb r7, [r10, #TI_USED_CP + 10] @ mark CP#10 as used
+ strb r7, [r10, #TI_USED_CP + 11] @ mark CP#11 as used
+ b do_vfp @ let VFP handler handle this
+1:
+#endif
tst r0, #0x08000000 @ only CDP/CPRT/LDC/STC have bit 27
#if defined(CONFIG_CPU_ARM610) || defined(CONFIG_CPU_ARM710)
and r8, r0, #0x0f000000 @ mask out op-code bits
mov pc, lr @ CP#14 (Debug)
mov pc, lr @ CP#15 (Control)
+#ifdef CONFIG_NEON
+ .align 6
+
+.LCneon_opcodes:
+ .word 0xfe000000 @ mask
+ .word 0xf2000000 @ opcode
+
+ .word 0xff100000 @ mask
+ .word 0xf4000000 @ opcode
+
+ .word 0x00000000 @ mask
+ .word 0x00000000 @ opcode
+#endif
+
do_fpe:
enable_irq
ldr r4, .LCfp
.data
ENTRY(fp_enter)
.word no_fp
- .text
+ .previous
no_fp: mov pc, lr
__pabt_usr:
usr_entry
+#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)
+#endif
enable_irq @ Enable interrupts
- mov r0, r2 @ address (pc)
mov r1, sp @ regs
bl do_PrefetchAbort @ call abort handler
/* fall through */
*
* Clobbered:
*
- * the Z flag might be lost
+ * none
*
* Definition and user space usage example:
*
*
* - This routine already includes memory barriers as needed.
*
- * - A failure might be transient, i.e. it is possible, although unlikely,
- * that "failure" be returned even if *ptr == oldval.
- *
* For example, a user space atomic_add implementation could look like this:
*
* #define atomic_add(ptr, val) \
#elif __LINUX_ARM_ARCH__ < 6
+#ifdef CONFIG_MMU
+
/*
- * Theory of operation:
- *
- * We set the Z flag before loading oldval. If ever an exception
- * occurs we can not be sure the loaded value will still be the same
- * when the exception returns, therefore the user exception handler
- * will clear the Z flag whenever the interrupted user code was
- * actually from the kernel address space (see the usr_entry macro).
- *
- * The post-increment on the str is used to prevent a race with an
- * exception happening just after the str instruction which would
- * clear the Z flag although the exchange was done.
+ * The only thing that can break atomicity in this cmpxchg
+ * implementation is either an IRQ or a data abort exception
+ * causing another process/thread to be scheduled in the middle
+ * of the critical sequence. To prevent this, code is added to
+ * the IRQ and data abort exception handlers to set the pc back
+ * to the beginning of the critical section if it is found to be
+ * within that critical section (see kuser_cmpxchg_fixup).
*/
-#ifdef CONFIG_MMU
- teq ip, ip @ set Z flag
- ldr ip, [r2] @ load current val
- add r3, r2, #1 @ prepare store ptr
- teqeq ip, r0 @ compare with oldval if still allowed
- streq r1, [r3, #-1]! @ store newval if still allowed
- subs r0, r2, r3 @ if r2 == r3 the str occured
+1: ldr r3, [r2] @ load current val
+ subs r3, r3, r0 @ compare with oldval
+2: streq r1, [r2] @ store newval if eq
+ rsbs r0, r3, #0 @ set return val and C flag
+ usr_ret lr
+
+ .text
+kuser_cmpxchg_fixup:
+ @ Called from kuser_cmpxchg_check macro.
+ @ r2 = address of interrupted insn (must be preserved).
+ @ sp = saved regs. r7 and r8 are clobbered.
+ @ 1b = first critical insn, 2b = last critical insn.
+ @ If r2 >= 1b and r2 <= 2b then saved pc_usr is set to 1b.
+ mov r7, #0xffff0fff
+ sub r7, r7, #(0xffff0fff - (0xffff0fc0 + (1b - __kuser_cmpxchg)))
+ subs r8, r2, r7
+ rsbcss r8, r8, #(2b - 1b)
+ strcs r7, [sp, #S_PC]
+ mov pc, lr
+ .previous
+
#else
#warning "NPTL on non MMU needs fixing"
mov r0, #-1
adds r0, r0, #0
-#endif
usr_ret lr
+#endif
#else
#ifdef CONFIG_SMP
mcr p15, 0, r0, c7, c10, 5 @ dmb
#endif
- ldrex r3, [r2]
+1: ldrex r3, [r2]
subs r3, r3, r0
strexeq r3, r1, [r2]
+ teqeq r3, #1
+ beq 1b
rsbs r0, r3, #0
+ /* beware -- each __kuser slot must be 8 instructions max */
#ifdef CONFIG_SMP
- mcr p15, 0, r0, c7, c10, 5 @ dmb
-#endif
+ b __kuser_memory_barrier
+#else
usr_ret lr
+#endif
#endif
*
* Clobbered:
*
- * the Z flag might be lost
+ * none
*
* Definition and user space usage example:
*
projects / GitHub / mt8127 / android_kernel_alcatel_ttab.git / blobdiff