summaryrefslogtreecommitdiff
path: root/arch/arm64/kernel/armv8_deprecated.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm64/kernel/armv8_deprecated.c')
-rw-r--r--arch/arm64/kernel/armv8_deprecated.c36
1 files changed, 22 insertions, 14 deletions
diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c
index 42ffdb54e162..b0988bb1bf64 100644
--- a/arch/arm64/kernel/armv8_deprecated.c
+++ b/arch/arm64/kernel/armv8_deprecated.c
@@ -280,35 +280,43 @@ static void __init register_insn_emulation_sysctl(struct ctl_table *table)
/*
* Error-checking SWP macros implemented using ldxr{b}/stxr{b}
*/
-#define __user_swpX_asm(data, addr, res, temp, B) \
+
+/* Arbitrary constant to ensure forward-progress of the LL/SC loop */
+#define __SWP_LL_SC_LOOPS 4
+
+#define __user_swpX_asm(data, addr, res, temp, temp2, B) \
__asm__ __volatile__( \
+ " mov %w3, %w7\n" \
ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_HAS_PAN, \
CONFIG_ARM64_PAN) \
- "0: ldxr"B" %w2, [%3]\n" \
- "1: stxr"B" %w0, %w1, [%3]\n" \
+ "0: ldxr"B" %w2, [%4]\n" \
+ "1: stxr"B" %w0, %w1, [%4]\n" \
" cbz %w0, 2f\n" \
- " mov %w0, %w4\n" \
+ " sub %w3, %w3, #1\n" \
+ " cbnz %w3, 0b\n" \
+ " mov %w0, %w5\n" \
" b 3f\n" \
"2:\n" \
" mov %w1, %w2\n" \
"3:\n" \
" .pushsection .fixup,\"ax\"\n" \
" .align 2\n" \
- "4: mov %w0, %w5\n" \
+ "4: mov %w0, %w6\n" \
" b 3b\n" \
" .popsection" \
_ASM_EXTABLE(0b, 4b) \
_ASM_EXTABLE(1b, 4b) \
ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_HAS_PAN, \
CONFIG_ARM64_PAN) \
- : "=&r" (res), "+r" (data), "=&r" (temp) \
- : "r" (addr), "i" (-EAGAIN), "i" (-EFAULT) \
+ : "=&r" (res), "+r" (data), "=&r" (temp), "=&r" (temp2) \
+ : "r" (addr), "i" (-EAGAIN), "i" (-EFAULT), \
+ "i" (__SWP_LL_SC_LOOPS) \
: "memory")
-#define __user_swp_asm(data, addr, res, temp) \
- __user_swpX_asm(data, addr, res, temp, "")
-#define __user_swpb_asm(data, addr, res, temp) \
- __user_swpX_asm(data, addr, res, temp, "b")
+#define __user_swp_asm(data, addr, res, temp, temp2) \
+ __user_swpX_asm(data, addr, res, temp, temp2, "")
+#define __user_swpb_asm(data, addr, res, temp, temp2) \
+ __user_swpX_asm(data, addr, res, temp, temp2, "b")
/*
* Bit 22 of the instruction encoding distinguishes between
@@ -328,12 +336,12 @@ static int emulate_swpX(unsigned int address, unsigned int *data,
}
while (1) {
- unsigned long temp;
+ unsigned long temp, temp2;
if (type == TYPE_SWPB)
- __user_swpb_asm(*data, address, res, temp);
+ __user_swpb_asm(*data, address, res, temp, temp2);
else
- __user_swp_asm(*data, address, res, temp);
+ __user_swp_asm(*data, address, res, temp, temp2);
if (likely(res != -EAGAIN) || signal_pending(current))
break;