diff options
| author | Max Filippov | 2021-07-25 16:31:34 -0700 |
|---|---|---|
| committer | Max Filippov | 2021-10-18 22:19:34 -0700 |
| commit | 61a6b91283b4c9e308fcf9377d3f0598ceccb252 (patch) | |
| tree | 8d96ceb3f4f4bbd4bf6deff7822814008e9459d0 /arch/xtensa/lib | |
| parent | d191323bc02370667fede74228135440efd98d2b (diff) | |
xtensa: don't use a12 in __xtensa_copy_user in call0 ABI
a12 is callee-saved register in xtensa call0 ABI, so a function must not
change it. The main unaligned copy loop of __xtensa_copy_user uses all
low-numbered registers, so a register must be spilled to avoid using a12
as a loop counter.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Diffstat (limited to 'arch/xtensa/lib')
| -rw-r--r-- | arch/xtensa/lib/usercopy.S | 28 |
1 files changed, 22 insertions, 6 deletions
diff --git a/arch/xtensa/lib/usercopy.S b/arch/xtensa/lib/usercopy.S index a0aa4047f94a..16128c094c62 100644 --- a/arch/xtensa/lib/usercopy.S +++ b/arch/xtensa/lib/usercopy.S @@ -60,7 +60,12 @@ .text ENTRY(__xtensa_copy_user) - abi_entry_default +#if !XCHAL_HAVE_LOOPS && defined(__XTENSA_CALL0_ABI__) +#define STACK_SIZE 4 +#else +#define STACK_SIZE 0 +#endif + abi_entry(STACK_SIZE) # a2/ dst, a3/ src, a4/ len mov a5, a2 # copy dst so that a2 is return value mov a11, a4 # preserve original len for error case @@ -75,7 +80,7 @@ ENTRY(__xtensa_copy_user) __ssa8 a3 # set shift amount from byte offset bnez a4, .Lsrcunaligned movi a2, 0 # return success for len==0 - abi_ret_default + abi_ret(STACK_SIZE) /* * Destination is unaligned @@ -127,7 +132,7 @@ EX(10f) s8i a6, a5, 0 #endif /* !XCHAL_HAVE_LOOPS */ .Lbytecopydone: movi a2, 0 # return success for len bytes copied - abi_ret_default + abi_ret(STACK_SIZE) /* * Destination and source are word-aligned. @@ -187,7 +192,7 @@ EX(10f) l8ui a6, a3, 0 EX(10f) s8i a6, a5, 0 .L5: movi a2, 0 # return success for len bytes copied - abi_ret_default + abi_ret(STACK_SIZE) /* * Destination is aligned, Source is unaligned @@ -205,8 +210,14 @@ EX(10f) l32i a6, a3, 0 # load first word loopnez a7, .Loop2done #else /* !XCHAL_HAVE_LOOPS */ beqz a7, .Loop2done +#if defined(__XTENSA_CALL0_ABI__) + s32i a10, a1, 0 + slli a10, a7, 4 + add a10, a10, a3 # a10 = end of last 16B source chunk +#else slli a12, a7, 4 add a12, a12, a3 # a12 = end of last 16B source chunk +#endif #endif /* !XCHAL_HAVE_LOOPS */ .Loop2: EX(10f) l32i a7, a3, 4 @@ -224,7 +235,12 @@ EX(10f) s32i a8, a5, 8 EX(10f) s32i a9, a5, 12 addi a5, a5, 16 #if !XCHAL_HAVE_LOOPS +#if defined(__XTENSA_CALL0_ABI__) + blt a3, a10, .Loop2 + l32i a10, a1, 0 +#else blt a3, a12, .Loop2 +#endif #endif /* !XCHAL_HAVE_LOOPS */ .Loop2done: bbci.l a4, 3, .L12 @@ -264,7 +280,7 @@ EX(10f) l8ui a6, a3, 0 EX(10f) s8i a6, a5, 0 .L15: movi a2, 0 # return success for len bytes copied - abi_ret_default + abi_ret(STACK_SIZE) ENDPROC(__xtensa_copy_user) @@ -281,4 +297,4 @@ ENDPROC(__xtensa_copy_user) 10: sub a2, a5, a2 /* a2 <-- bytes copied */ sub a2, a11, a2 /* a2 <-- bytes not copied */ - abi_ret_default + abi_ret(STACK_SIZE) |