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| author | Willy Tarreau <w@1wt.eu> | 2023-01-10 08:24:29 +0100 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2023-01-10 22:33:56 +0100 |
| commit | 041fa97cb332e59311aa861fac3be178abad6a9b (patch) | |
| tree | 11182e834e02832cedc133c4098826db41e6e74b /tools/include | |
| parent | tools/nolibc: add auxiliary vector retrieval for arm (diff) | |
| download | linux-041fa97cb332e59311aa861fac3be178abad6a9b.tar.xz linux-041fa97cb332e59311aa861fac3be178abad6a9b.zip | |
tools/nolibc: add auxiliary vector retrieval for riscv
In the _start block we now iterate over envp to find the auxiliary
vector after the NULL. The pointer is saved into an _auxv variable
that is marked as weak so that it's accessible from multiple units.
It was tested on riscv64 only.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'tools/include')
| -rw-r--r-- | tools/include/nolibc/arch-riscv.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/tools/include/nolibc/arch-riscv.h b/tools/include/nolibc/arch-riscv.h index 1608e6bd94b9..e197fcb10ac0 100644 --- a/tools/include/nolibc/arch-riscv.h +++ b/tools/include/nolibc/arch-riscv.h @@ -171,6 +171,7 @@ struct sys_stat_struct { }) char **environ __attribute__((weak)); +const unsigned long *_auxv __attribute__((weak)); /* startup code */ void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) _start(void) @@ -185,6 +186,15 @@ void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) _start(void) "slli a2, a0, "PTRLOG"\n" // envp (a2) = SZREG*argc ... "add a2, a2, "SZREG"\n" // + SZREG (skip null) "add a2,a2,a1\n" // + argv + + "add a3, a2, zero\n" // iterate a3 over envp to find auxv (after NULL) + "0:\n" // do { + "ld a4, 0(a3)\n" // a4 = *a3; + "add a3, a3, "SZREG"\n" // a3 += sizeof(void*); + "bne a4, zero, 0b\n" // } while (a4); + "lui a4, %hi(_auxv)\n" // a4 = &_auxv (high bits) + "sd a3, %lo(_auxv)(a4)\n" // store a3 into _auxv + "lui a3, %hi(environ)\n" // a3 = &environ (high bits) "sd a2,%lo(environ)(a3)\n" // store envp(a2) into environ "andi sp,a1,-16\n" // sp must be 16-byte aligned |