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riscv: Fix incorrect jal with HIDDEN_JUMPTARGET

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A non-local STV_DEFAULT defined symbol is by default preemptible in a
shared object. j/jal cannot target a preemptible symbol. On other
architectures, such a jump instruction either causes PLT [BZ #18822], or
if short-ranged, sometimes rejected by the linker (but not by GNU ld's
riscv port [ld PR/28509]).

Use HIDDEN_JUMPTARGET to target a non-preemptible symbol instead.

With this patch, ld.so and libc.so can be linked with LLD if source
files are compiled/assembled with -mno-relax/-Wa,-mno-relax.

Acked-by: Palmer Dabbelt <palmer@dabbelt.com>
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
This commit is contained in:
Fangrui Song
2021-10-28 11:39:49 -07:00
parent 9b7cfab180
commit 6838920383
2 changed files with 4 additions and 3 deletions
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2
sysdeps/riscv/setjmp.S
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@@ -21,7 +21,7 @@
ENTRY (_setjmp) ENTRY (_setjmp)
li a1, 0 li a1, 0
j __sigsetjmp j HIDDEN_JUMPTARGET (__sigsetjmp)
END (_setjmp) END (_setjmp)
ENTRY (setjmp) ENTRY (setjmp)
li a1, 1 li a1, 1

5
sysdeps/unix/sysv/linux/riscv/setcontext.S
View File

@@ -95,6 +95,7 @@ LEAF (__setcontext)
99: j __syscall_error 99: j __syscall_error
END (__setcontext) END (__setcontext)
libc_hidden_def (__setcontext)
weak_alias (__setcontext, setcontext) weak_alias (__setcontext, setcontext)
LEAF (__start_context) LEAF (__start_context)
@@ -108,7 +109,7 @@ LEAF (__start_context)
/* Invoke subsequent context if present, else exit(0). */ /* Invoke subsequent context if present, else exit(0). */
mv a0, s2 mv a0, s2
beqz s2, 1f beqz s2, 1f
jal __setcontext jal HIDDEN_JUMPTARGET (__setcontext)
1: j exit 1: j HIDDEN_JUMPTARGET (exit)
END (__start_context) END (__start_context)