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| author | Rich Felker <dalias@aerifal.cx> | 2015-05-25 19:15:17 -0400 |
|---|---|---|
| committer | Rich Felker <dalias@aerifal.cx> | 2015-05-25 19:15:17 -0400 |
| commit | 768b82c6de24e480267c4c251c440edfc71800e3 (patch) | |
| tree | 9b59e909041b2ad6ca35dad514ad9fa5c5379894 | |
| parent | 967bcbf67c3ffac587de4d79abc1e5e072d83e3e (diff) | |
| download | musl-768b82c6de24e480267c4c251c440edfc71800e3.tar.gz | |
move call to dynamic linker stage-3 into stage-2 function
this move eliminates a duplicate "by-hand" symbol lookup loop from the
stage-1 code and replaces it with a call to find_sym, which can be
used once we're in stage 2. it reduces the size of the stage 1 code,
which is helpful because stage 1 will become the crt start file for
static-PIE executables, and it will allow stage 3 to access stage 2's
automatic storage, which will be important in an upcoming commit.
| -rw-r--r-- | src/internal/dynlink.h | 2 | ||||
| -rw-r--r-- | src/ldso/dlstart.c | 11 | ||||
| -rw-r--r-- | src/ldso/dynlink.c | 8 |
3 files changed, 9 insertions, 12 deletions
diff --git a/src/internal/dynlink.h b/src/internal/dynlink.h index 53661d62..8621d2dd 100644 --- a/src/internal/dynlink.h +++ b/src/internal/dynlink.h @@ -51,7 +51,7 @@ enum { #define AUX_CNT 32 #define DYN_CNT 32 -typedef void (*stage2_func)(unsigned char *); +typedef void (*stage2_func)(unsigned char *, size_t *); typedef _Noreturn void (*stage3_func)(size_t *); #endif diff --git a/src/ldso/dlstart.c b/src/ldso/dlstart.c index 5f84465c..3aaa200f 100644 --- a/src/ldso/dlstart.c +++ b/src/ldso/dlstart.c @@ -84,16 +84,7 @@ void _dlstart_c(size_t *sp, size_t *dynv) && s[3]=='l' && s[4]=='s' && s[5]=='2' && !s[6]) break; } - ((stage2_func)(base + syms[i].st_value))(base); - - /* Call dynamic linker stage-3, __dls3 */ - for (i=0; ;i++) { - const char *s = strings + syms[i].st_name; - if (s[0]=='_' && s[1]=='_' && s[2]=='d' - && s[3]=='l' && s[4]=='s' && s[5]=='3' && !s[6]) - break; - } - ((stage3_func)(base + syms[i].st_value))(sp); + ((stage2_func)(base + syms[i].st_value))(base, sp); } #endif diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c index 93595a0f..3842aeba 100644 --- a/src/ldso/dynlink.c +++ b/src/ldso/dynlink.c @@ -1116,7 +1116,7 @@ static void update_tls_size() * linker itself, but some of the relocations performed may need to be * replaced later due to copy relocations in the main program. */ -void __dls2(unsigned char *base) +void __dls2(unsigned char *base, size_t *sp) { Ehdr *ehdr = (void *)base; ldso.base = base; @@ -1134,6 +1134,12 @@ void __dls2(unsigned char *base) ldso.relocated = 0; ldso.rel_update_got = 1; + + /* Call dynamic linker stage-3, __dls3, looking it up + * symbolically as a barrier against moving the address + * load across the above relocation processing. */ + struct symdef dls3_def = find_sym(&ldso, "__dls3", 0); + ((stage3_func)(ldso.base+dls3_def.sym->st_value))(sp); } /* Stage 3 of the dynamic linker is called with the dynamic linker/libc |