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| author | Rich Felker <dalias@aerifal.cx> | 2018-10-01 19:36:14 -0400 |
|---|---|---|
| committer | Rich Felker <dalias@aerifal.cx> | 2018-10-01 19:39:24 -0400 |
| commit | 7bf773a8f9b97875ba67b646c1681ac5ca22016f (patch) | |
| tree | 5647df1752aef1f7e862c54a4ff7e494defc32bd /src/ldso | |
| parent | 0beb9dfbecad38af9759b1e83eeb007e28b70abb (diff) | |
| download | musl-7bf773a8f9b97875ba67b646c1681ac5ca22016f.tar.gz musl-7bf773a8f9b97875ba67b646c1681ac5ca22016f.tar.xz musl-7bf773a8f9b97875ba67b646c1681ac5ca22016f.zip | |
inline cp15 thread pointer load in arm dynamic TLSDESC asm when possible
the indirect function call is a significant portion of the code path for the dynamic case, and most users are probably building for ISA levels where it can be omitted. we could drop at least one register save/restore (lr) with this change, and possibly another (ip) with some clever shuffling, but it's not clear whether there's a way to do it that's not more expensive, or whether avoiding the save/restore would have any practical effect, so in the interest of avoiding complexity it's omitted for now.
Diffstat (limited to 'src/ldso')
| -rw-r--r-- | src/ldso/arm/tlsdesc.S | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/src/ldso/arm/tlsdesc.S b/src/ldso/arm/tlsdesc.S index f3d67fce..b81f3111 100644 --- a/src/ldso/arm/tlsdesc.S +++ b/src/ldso/arm/tlsdesc.S @@ -19,6 +19,10 @@ __tlsdesc_dynamic: ldr r2,[r1,#4] // r2 = offset ldr r1,[r1] // r1 = modid +#if ((__ARM_ARCH_6K__ || __ARM_ARCH_6KZ__ || __ARM_ARCH_6ZK__) && !__thumb__) \ + || __ARM_ARCH_7A__ || __ARM_ARCH_7R__ || __ARM_ARCH >= 7 + mrc p15,0,r0,c13,c0,3 +#else ldr r0,1f add r0,r0,pc ldr r0,[r0] @@ -29,6 +33,7 @@ __tlsdesc_dynamic: mov lr,pc bx r0 #endif +#endif ldr r3,[r0,#-4] // r3 = dtv ldr ip,[r3] // ip = dtv slot count cmp r1,ip @@ -58,5 +63,9 @@ __tlsdesc_dynamic: sub r0,r0,r1 // r0 = retval-tp b 4b +#if ((__ARM_ARCH_6K__ || __ARM_ARCH_6KZ__ || __ARM_ARCH_6ZK__) && !__thumb__) \ + || __ARM_ARCH_7A__ || __ARM_ARCH_7R__ || __ARM_ARCH >= 7 +#else .align 2 1: .word __a_gettp_ptr - 2b +#endif |