common-user: Adjust system call return on FreeBSD
FreeBSD system calls return positive errno. On the 4 hosts for
which we have support, error is indicated by the C bit set or clear.
Reviewed-by: Warner Losh <imp@bsdimp.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
diff --git a/common-user/host/aarch64/safe-syscall.inc.S b/common-user/host/aarch64/safe-syscall.inc.S
index 73a04b7..b8fd5b5 100644
--- a/common-user/host/aarch64/safe-syscall.inc.S
+++ b/common-user/host/aarch64/safe-syscall.inc.S
@@ -60,17 +60,29 @@
cbnz w10, 2f
svc 0x0
safe_syscall_end:
+
/* code path for having successfully executed the syscall */
+#if defined(__linux__)
+ /* Linux kernel returns (small) negative errno. */
cmp x0, #-4096
b.hi 0f
+#elif defined(__FreeBSD__)
+ /* FreeBSD kernel returns positive errno and C bit set. */
+ b.cs 1f
+#else
+#error "unsupported os"
+#endif
ret
+#if defined(__linux__)
/* code path setting errno */
0: neg w0, w0
b safe_syscall_set_errno_tail
+#endif
/* code path when we didn't execute the syscall */
2: mov w0, #QEMU_ERESTARTSYS
- b safe_syscall_set_errno_tail
+1: b safe_syscall_set_errno_tail
+
.cfi_endproc
.size safe_syscall_base, .-safe_syscall_base
diff --git a/common-user/host/arm/safe-syscall.inc.S b/common-user/host/arm/safe-syscall.inc.S
index 66176a9..bbfb896 100644
--- a/common-user/host/arm/safe-syscall.inc.S
+++ b/common-user/host/arm/safe-syscall.inc.S
@@ -74,10 +74,19 @@
bne 2f
swi 0
safe_syscall_end:
+
/* code path for having successfully executed the syscall */
+#if defined(__linux__)
+ /* Linux kernel returns (small) negative errno. */
cmp r0, #-4096
neghi r0, r0
bhi 1f
+#elif defined(__FreeBSD__)
+ /* FreeBSD kernel returns positive errno and C bit set. */
+ bcs 1f
+#else
+#error "unsupported os"
+#endif
pop { r4, r5, r6, r7, r8, pc }
/* code path when we didn't execute the syscall */
diff --git a/common-user/host/i386/safe-syscall.inc.S b/common-user/host/i386/safe-syscall.inc.S
index aced8c5..baf5400 100644
--- a/common-user/host/i386/safe-syscall.inc.S
+++ b/common-user/host/i386/safe-syscall.inc.S
@@ -71,9 +71,18 @@
mov 8+16(%esp), %eax /* syscall number */
int $0x80
safe_syscall_end:
+
/* code path for having successfully executed the syscall */
+#if defined(__linux__)
+ /* Linux kernel returns (small) negative errno. */
cmp $-4095, %eax
jae 0f
+#elif defined(__FreeBSD__)
+ /* FreeBSD kernel returns positive errno and C bit set. */
+ jc 1f
+#else
+#error "unsupported os"
+#endif
pop %ebx
.cfi_remember_state
.cfi_adjust_cfa_offset -4
@@ -90,8 +99,10 @@
ret
.cfi_restore_state
+#if defined(__linux__)
0: neg %eax
jmp 1f
+#endif
/* code path when we didn't execute the syscall */
2: mov $QEMU_ERESTARTSYS, %eax
diff --git a/common-user/host/x86_64/safe-syscall.inc.S b/common-user/host/x86_64/safe-syscall.inc.S
index 84fed20..a20927a 100644
--- a/common-user/host/x86_64/safe-syscall.inc.S
+++ b/common-user/host/x86_64/safe-syscall.inc.S
@@ -68,9 +68,18 @@
jnz 2f
syscall
safe_syscall_end:
+
/* code path for having successfully executed the syscall */
+#if defined(__linux__)
+ /* Linux kernel returns (small) negative errno. */
cmp $-4095, %rax
jae 0f
+#elif defined(__FreeBSD__)
+ /* FreeBSD kernel returns positive errno and C bit set. */
+ jc 1f
+#else
+#error "unsupported os"
+#endif
pop %rbp
.cfi_remember_state
.cfi_def_cfa_offset 8
@@ -78,8 +87,10 @@
ret
.cfi_restore_state
+#if defined(__linux__)
0: neg %eax
jmp 1f
+#endif
/* code path when we didn't execute the syscall */
2: mov $QEMU_ERESTARTSYS, %eax