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author | Szabolcs Nagy <nsz@port70.net> | 2018-06-02 01:52:01 +0200 |
---|---|---|
committer | Rich Felker <dalias@aerifal.cx> | 2018-06-02 19:38:44 -0400 |
commit | 610c5a8524c3d6cd3ac5a5f1231422e7648a3791 (patch) | |
tree | a0d9b1b9b4dd950a475c95151b388472374699fa /arch/arm | |
parent | 029c622a89bf8cc15fd9fd56e8e88465ca6130cf (diff) | |
download | musl-610c5a8524c3d6cd3ac5a5f1231422e7648a3791.zip musl-610c5a8524c3d6cd3ac5a5f1231422e7648a3791.tar.gz musl-610c5a8524c3d6cd3ac5a5f1231422e7648a3791.tar.bz2 |
fix TLS layout of TLS variant I when there is a gap above TP
In TLS variant I the TLS is above TP (or above a fixed offset from TP)
but on some targets there is a reserved gap above TP before TLS starts.
This matters for the local-exec tls access model when the offsets of
TLS variables from the TP are hard coded by the linker into the
executable, so the libc must compute these offsets the same way as the
linker. The tls offset of the main module has to be
alignup(GAP_ABOVE_TP, main_tls_align).
If there is no TLS in the main module then the gap can be ignored
since musl does not use it and the tls access models of shared
libraries are not affected.
The previous setup only worked if (tls_align & -GAP_ABOVE_TP) == 0
(i.e. TLS did not require large alignment) because the gap was
treated as a fixed offset from TP. Now the TP points at the end
of the pthread struct (which is aligned) and there is a gap above
it (which may also need alignment).
The fix required changing TP_ADJ and __pthread_self on affected
targets (aarch64, arm and sh) and in the tlsdesc asm the offset to
access the dtv changed too.
Diffstat (limited to 'arch/arm')
-rw-r--r-- | arch/arm/pthread_arch.h | 7 | ||||
-rw-r--r-- | arch/arm/reloc.h | 2 |
2 files changed, 5 insertions, 4 deletions
diff --git a/arch/arm/pthread_arch.h b/arch/arm/pthread_arch.h index 6657e19..8f2ae8f 100644 --- a/arch/arm/pthread_arch.h +++ b/arch/arm/pthread_arch.h @@ -5,7 +5,7 @@ static inline pthread_t __pthread_self() { char *p; __asm__ __volatile__ ( "mrc p15,0,%0,c13,c0,3" : "=r"(p) ); - return (void *)(p+8-sizeof(struct pthread)); + return (void *)(p-sizeof(struct pthread)); } #else @@ -21,12 +21,13 @@ static inline pthread_t __pthread_self() extern uintptr_t __attribute__((__visibility__("hidden"))) __a_gettp_ptr; register uintptr_t p __asm__("r0"); __asm__ __volatile__ ( BLX " %1" : "=r"(p) : "r"(__a_gettp_ptr) : "cc", "lr" ); - return (void *)(p+8-sizeof(struct pthread)); + return (void *)(p-sizeof(struct pthread)); } #endif #define TLS_ABOVE_TP -#define TP_ADJ(p) ((char *)(p) + sizeof(struct pthread) - 8) +#define GAP_ABOVE_TP 8 +#define TP_ADJ(p) ((char *)(p) + sizeof(struct pthread)) #define MC_PC arm_pc diff --git a/arch/arm/reloc.h b/arch/arm/reloc.h index b175711..4b00bf6 100644 --- a/arch/arm/reloc.h +++ b/arch/arm/reloc.h @@ -16,7 +16,7 @@ #define NO_LEGACY_INITFINI -#define TPOFF_K 8 +#define TPOFF_K 0 #define REL_SYMBOLIC R_ARM_ABS32 #define REL_GOT R_ARM_GLOB_DAT |