diff options
Diffstat (limited to 'sysdeps/arm/elf/start.S')
| -rw-r--r-- | sysdeps/arm/elf/start.S | 81 |
1 files changed, 24 insertions, 57 deletions
diff --git a/sysdeps/arm/elf/start.S b/sysdeps/arm/elf/start.S index e0964a1e38..13b9c780ef 100644 --- a/sysdeps/arm/elf/start.S +++ b/sysdeps/arm/elf/start.S @@ -24,19 +24,19 @@ This includes _init and _libc_init - At this entry point, most registers' values are unspecified, except for: + At this entry point, most registers' values are unspecified, except: - r0 Contains a function pointer to be registered with `atexit'. + a1 Contains a function pointer to be registered with `atexit'. This is how the dynamic linker arranges to have DT_FINI functions called for shared libraries that have been loaded before this code runs. sp The stack contains the arguments and environment: - 0(%esp) argc - 4(%esp) argv[0] + 0(sp) argc + 4(sp) argv[0] ... - (4*argc)(%esp) NULL - (4*(argc+1))(%esp) envp[0] + (4*argc)(sp) NULL + (4*(argc+1))(sp) envp[0] ... NULL */ @@ -44,62 +44,29 @@ .text .globl _start _start: - /* Clear the frame pointer. The Intel ABI suggests this be done, - to mark the outermost frame obviously. This seems like a - sensible thing to do */ + /* Clear the frame pointer since this is the outermost frame. */ mov fp, #0 - /* r0 contains the address of the shared library termination - function, which we will register with `atexit' to be called by - `exit'. I suspect that on some systems, and when statically - linked, this will not be set by anything to any function - pointer; hopefully it will be zero so we don't try to call - random pointers. */ - cmp r0,#0 - blne atexit(PLT) - - /* Do essential libc initialization. In statically linked - programs under the GNU Hurd, this is what sets up the - arguments on the stack for the code below. For dyn-link - programs, this has been run already, in the .init code. */ -#ifndef PIC - bl __libc_init_first - - /* Extract the arguments and environment as encoded on the stack - and set up the arguments for `main': argc, argv, envp. */ - ldr r0,[sp] - add r1,sp,#4 - add r2,r1,r0,lsl #2 - add r2,r2,#4 - /* save a copy of envp while we have it */ - ldr r3,L_environ - str r2,[r3] - - /* Call `_init', which is the entry point to our own `.init' - section; and register with `atexit' to have `exit' call - `_fini', which is the entry point to our own `.fini' section. */ - bl _init - ldr r0,L_fini - bl atexit - b L_pfini - -L_fini: .word _fini -L_environ: .word _environ -L_pfini: -#endif - /* rebuild the arg list for main() */ - ldr r0,[sp] - add r1,sp,#4 - add r2,r1,r0,lsl #2 - add r2,r2,#4 - - /* Call the user's main function, and exit with its value. */ - bl main - bl exit + /* Pop argc off the stack and save a pointer to argv */ + ldmfd sp!, {a2} + mov a3, sp + + /* Push the last arguments to main() onto the stack */ + stmfd sp!, {a1} + ldr a1, =_fini + stmfd sp!, {a1} + + /* Set up the other arguments for main() that go in registers */ + ldr a1, =main + ldr a4, =_init + + /* __libc_start_main (main, argc, argv, init, fini, rtld_fini) */ + + /* Let the libc call main and exit with its return code. */ + bl __libc_start_main /* should never get here....*/ bl abort - /* Define a symbol for the first piece of initialized data. */ .data .globl __data_start |