apply FEAT_LSUI instruction to emulate deprecated swpX instruction.
Signed-off-by: Yeoreum Yun yeoreum.yun@arm.com --- arch/arm64/kernel/armv8_deprecated.c | 77 +++++++++++++++++++++++++--- 1 file changed, 71 insertions(+), 6 deletions(-)
diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c index d15e35f1075c..b8e6d71f766d 100644 --- a/arch/arm64/kernel/armv8_deprecated.c +++ b/arch/arm64/kernel/armv8_deprecated.c @@ -13,6 +13,7 @@ #include <linux/uaccess.h>
#include <asm/cpufeature.h> +#include <asm/lsui.h> #include <asm/insn.h> #include <asm/sysreg.h> #include <asm/system_misc.h> @@ -86,13 +87,77 @@ static unsigned int __maybe_unused aarch32_check_condition(u32 opcode, u32 psr) * Rn = address */
+/* Arbitrary constant to ensure forward-progress of the loop */ +#define __SWP_LOOPS 4 + +#ifdef CONFIG_AS_HAS_LSUI +static __always_inline int +__lsui_user_swp_asm(unsigned int *data, unsigned int addr) +{ + int err = 0; + unsigned int temp; + + asm volatile("// __lsui_user_swp_asm\n" + __LSUI_PREAMBLE + "1: swpt %w1, %w2, [%3]\n" + " mov %w1, %w2\n" + "2:\n" + _ASM_EXTABLE_UACCESS_ERR(1b, 2b, %w0) + : "+r" (err), "+r" (*data), "=&r" (temp) + : "r" ((unsigned long)addr) + : "memory"); + + return err; +} + +static __always_inline int +__lsui_user_swpb_asm(unsigned int *data, unsigned int addr) +{ + u8 i, idx; + int err = -EAGAIN; + u64 __user *addr_al; + u64 oldval; + union { + u64 var; + u8 raw[sizeof(u64)]; + } newval, curval; + + idx = addr & (sizeof(u64) - 1); + addr_al = (u64 __user *)ALIGN_DOWN(addr, sizeof(u64)); + + for (i = 0; i < __SWP_LOOPS; i++) { + if (get_user(oldval, addr_al)) + return -EFAULT; + + curval.var = newval.var = oldval; + newval.raw[idx] = *data; + + asm volatile("// __lsui_user_swpb_asm\n" + __LSUI_PREAMBLE + "1: cast %x2, %x3, %1\n" + "2:\n" + _ASM_EXTABLE_UACCESS_ERR(1b, 2b, %w0) + : "+r" (err), "+Q" (*addr_al), "+r" (curval.var) + : "r" (newval.var) + : "memory"); + + if (curval.var == oldval) { + err = 0; + break; + } + } + + if (!err) + *data = curval.raw[idx]; + + return err; +} +#endif /* CONFIG_AS_HAS_LSUI */ + /* * Error-checking SWP macros implemented using ldxr{b}/stxr{b} */
-/* Arbitrary constant to ensure forward-progress of the LL/SC loop */ -#define __SWP_LL_SC_LOOPS 4 - #define LLSC_USER_SWPX(B) \ static __always_inline int \ __llsc_user_swp##B##_asm(unsigned int *data, unsigned int addr) \ @@ -117,7 +182,7 @@ __llsc_user_swp##B##_asm(unsigned int *data, unsigned int addr) \ _ASM_EXTABLE_UACCESS_ERR(1b, 3b, %w0) \ : "=&r" (err), "+r" (*data), "=&r" (temp), "=&r" (temp2)\ : "r" ((unsigned long)addr), "i" (-EAGAIN), \ - "i" (__SWP_LL_SC_LOOPS) \ + "i" (__SWP_LOOPS) \ : "memory"); \ uaccess_disable_privileged(); \ \ @@ -128,9 +193,9 @@ LLSC_USER_SWPX() LLSC_USER_SWPX(b)
#define __user_swp_asm(data, addr) \ - __llsc_user_swp_asm(data, addr) + __lsui_llsc_body(user_swp_asm, data, addr) #define __user_swpb_asm(data, addr) \ - __llsc_user_swpb_asm(data, addr) + __lsui_llsc_body(user_swpb_asm, data, addr)
/* * Bit 22 of the instruction encoding distinguishes between