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author | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2021-12-30 17:08:36 +0000 |
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committer | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2022-05-17 10:14:03 +0100 |
commit | 1da064c015dce624cb19fcdc0bace7af2bd8caec (patch) | |
tree | d7da68d75f2cf23f909c0d97e0cbe8ea53946464 /sysdeps/aarch64/dl-machine.h | |
parent | 9faf5262c77487c96da8a3e961b88c0b1879e186 (diff) | |
download | glibc-1da064c015dce624cb19fcdc0bace7af2bd8caec.tar.gz glibc-1da064c015dce624cb19fcdc0bace7af2bd8caec.tar.xz glibc-1da064c015dce624cb19fcdc0bace7af2bd8caec.zip |
aarch64: Move ld.so _start to separate file and drop _dl_skip_args
A separate asm file is easier to maintain than a macro that expands to inline asm. The RTLD_START macro is only needed now because _dl_start is local in rtld.c, but _start has to call it, if _dl_start was made hidden then it could be empty. _dl_skip_args is no longer needed. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Diffstat (limited to 'sysdeps/aarch64/dl-machine.h')
-rw-r--r-- | sysdeps/aarch64/dl-machine.h | 77 |
1 files changed, 2 insertions, 75 deletions
diff --git a/sysdeps/aarch64/dl-machine.h b/sysdeps/aarch64/dl-machine.h index b40050a981..fe120bb507 100644 --- a/sysdeps/aarch64/dl-machine.h +++ b/sysdeps/aarch64/dl-machine.h @@ -105,81 +105,8 @@ elf_machine_runtime_setup (struct link_map *l, struct r_scope_elem *scope[], return lazy; } -/* Initial entry point for the dynamic linker. The C function - _dl_start is the real entry point, its return value is the user - program's entry point */ -#ifdef __LP64__ -# define RTLD_START RTLD_START_1 ("x", "3", "sp") -#else -# define RTLD_START RTLD_START_1 ("w", "2", "wsp") -#endif - - -#define RTLD_START_1(PTR, PTR_SIZE_LOG, PTR_SP) asm ("\ -.text \n\ -.globl _start \n\ -.type _start, %function \n\ -.globl _dl_start_user \n\ -.type _dl_start_user, %function \n\ -_start: \n\ - // bti c \n\ - hint 34 \n\ - mov " PTR "0, " PTR_SP " \n\ - bl _dl_start \n\ - // returns user entry point in x0 \n\ - mov x21, x0 \n\ -_dl_start_user: \n\ - // get the original arg count \n\ - ldr " PTR "1, [sp] \n\ - // get the argv address \n\ - add " PTR "2, " PTR_SP ", #(1<<" PTR_SIZE_LOG ") \n\ - // get _dl_skip_args to see if we were \n\ - // invoked as an executable \n\ - adrp x4, _dl_skip_args \n\ - ldr w4, [x4, #:lo12:_dl_skip_args] \n\ - // do we need to adjust argc/argv \n\ - cmp w4, 0 \n\ - beq .L_done_stack_adjust \n\ - // subtract _dl_skip_args from original arg count \n\ - sub " PTR "1, " PTR "1, " PTR "4 \n\ - // store adjusted argc back to stack \n\ - str " PTR "1, [sp] \n\ - // find the first unskipped argument \n\ - mov " PTR "3, " PTR "2 \n\ - add " PTR "4, " PTR "2, " PTR "4, lsl #" PTR_SIZE_LOG " \n\ - // shuffle argv down \n\ -1: ldr " PTR "5, [x4], #(1<<" PTR_SIZE_LOG ") \n\ - str " PTR "5, [x3], #(1<<" PTR_SIZE_LOG ") \n\ - cmp " PTR "5, #0 \n\ - bne 1b \n\ - // shuffle envp down \n\ -1: ldr " PTR "5, [x4], #(1<<" PTR_SIZE_LOG ") \n\ - str " PTR "5, [x3], #(1<<" PTR_SIZE_LOG ") \n\ - cmp " PTR "5, #0 \n\ - bne 1b \n\ - // shuffle auxv down \n\ -1: ldp " PTR "0, " PTR "5, [x4, #(2<<" PTR_SIZE_LOG ")]! \n\ - stp " PTR "0, " PTR "5, [x3], #(2<<" PTR_SIZE_LOG ") \n\ - cmp " PTR "0, #0 \n\ - bne 1b \n\ - // Update _dl_argv \n\ - adrp x3, __GI__dl_argv \n\ - str " PTR "2, [x3, #:lo12:__GI__dl_argv] \n\ -.L_done_stack_adjust: \n\ - // compute envp \n\ - add " PTR "3, " PTR "2, " PTR "1, lsl #" PTR_SIZE_LOG " \n\ - add " PTR "3, " PTR "3, #(1<<" PTR_SIZE_LOG ") \n\ - adrp x16, _rtld_local \n\ - add " PTR "16, " PTR "16, #:lo12:_rtld_local \n\ - ldr " PTR "0, [x16] \n\ - bl _dl_init \n\ - // load the finalizer function \n\ - adrp x0, _dl_fini \n\ - add " PTR "0, " PTR "0, #:lo12:_dl_fini \n\ - // jump to the user_s entry point \n\ - mov x16, x21 \n\ - br x16 \n\ -"); +/* In elf/rtld.c _dl_start should be global so dl-start.S can reference it. */ +#define RTLD_START asm (".globl _dl_start"); #define elf_machine_type_class(type) \ ((((type) == AARCH64_R(JUMP_SLOT) \ |