The j pseudoinstruction maps to a JAL instruction, which can only handle
a jump to somewhere with a signed 20-bit destination. In case of static
linking and LTO'ing this easily leads to "relocation truncated to fit"
error.
Switch to use tail pseudoinstruction, which is the standard way to
tail-call a function in medium code model (emits AUIPC+JALR).
Signed-off-by: Icenowy Zheng <uwu@icenowy.me>
---
P.S.
It seems that moving it to common-user/ makes the file out of the
MAINTAINERS section of "RISC-V TCG CPUS". I Manually added the
maintainers there, but the MAINTAINERS file seems to need a change on
this.
common-user/host/riscv/safe-syscall.inc.S | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/common-user/host/riscv/safe-syscall.inc.S b/common-user/host/riscv/safe-syscall.inc.S
index dfe83c300e..c8b81e33d0 100644
--- a/common-user/host/riscv/safe-syscall.inc.S
+++ b/common-user/host/riscv/safe-syscall.inc.S
@@ -69,11 +69,11 @@ safe_syscall_end:
/* code path setting errno */
0: neg a0, a0
- j safe_syscall_set_errno_tail
+ tail safe_syscall_set_errno_tail
/* code path when we didn't execute the syscall */
2: li a0, QEMU_ERESTARTSYS
- j safe_syscall_set_errno_tail
+ tail safe_syscall_set_errno_tail
.cfi_endproc
.size safe_syscall_base, .-safe_syscall_base
--
2.49.0On Thu, Apr 17, 2025 at 5:24 PM Icenowy Zheng <uwu@icenowy.me> wrote: > > The j pseudoinstruction maps to a JAL instruction, which can only handle > a jump to somewhere with a signed 20-bit destination. In case of static > linking and LTO'ing this easily leads to "relocation truncated to fit" > error. > > Switch to use tail pseudoinstruction, which is the standard way to > tail-call a function in medium code model (emits AUIPC+JALR). > > Signed-off-by: Icenowy Zheng <uwu@icenowy.me> Thanks! Applied to riscv-to-apply.next Alistair > --- > P.S. > It seems that moving it to common-user/ makes the file out of the > MAINTAINERS section of "RISC-V TCG CPUS". I Manually added the > maintainers there, but the MAINTAINERS file seems to need a change on > this. > > common-user/host/riscv/safe-syscall.inc.S | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/common-user/host/riscv/safe-syscall.inc.S b/common-user/host/riscv/safe-syscall.inc.S > index dfe83c300e..c8b81e33d0 100644 > --- a/common-user/host/riscv/safe-syscall.inc.S > +++ b/common-user/host/riscv/safe-syscall.inc.S > @@ -69,11 +69,11 @@ safe_syscall_end: > > /* code path setting errno */ > 0: neg a0, a0 > - j safe_syscall_set_errno_tail > + tail safe_syscall_set_errno_tail > > /* code path when we didn't execute the syscall */ > 2: li a0, QEMU_ERESTARTSYS > - j safe_syscall_set_errno_tail > + tail safe_syscall_set_errno_tail > > .cfi_endproc > .size safe_syscall_base, .-safe_syscall_base > -- > 2.49.0 > >
On 4/17/25 00:22, Icenowy Zheng wrote: > The j pseudoinstruction maps to a JAL instruction, which can only handle > a jump to somewhere with a signed 20-bit destination. In case of static > linking and LTO'ing this easily leads to "relocation truncated to fit" > error. > > Switch to use tail pseudoinstruction, which is the standard way to > tail-call a function in medium code model (emits AUIPC+JALR). > > Signed-off-by: Icenowy Zheng <uwu@icenowy.me> > --- > P.S. > It seems that moving it to common-user/ makes the file out of the > MAINTAINERS section of "RISC-V TCG CPUS". I Manually added the > maintainers there, but the MAINTAINERS file seems to need a change on > this. > > common-user/host/riscv/safe-syscall.inc.S | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) Reviewed-by: Richard Henderson <richard.henderson@linaro.org> r~ > > diff --git a/common-user/host/riscv/safe-syscall.inc.S b/common-user/host/riscv/safe-syscall.inc.S > index dfe83c300e..c8b81e33d0 100644 > --- a/common-user/host/riscv/safe-syscall.inc.S > +++ b/common-user/host/riscv/safe-syscall.inc.S > @@ -69,11 +69,11 @@ safe_syscall_end: > > /* code path setting errno */ > 0: neg a0, a0 > - j safe_syscall_set_errno_tail > + tail safe_syscall_set_errno_tail > > /* code path when we didn't execute the syscall */ > 2: li a0, QEMU_ERESTARTSYS > - j safe_syscall_set_errno_tail > + tail safe_syscall_set_errno_tail > > .cfi_endproc > .size safe_syscall_base, .-safe_syscall_base
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