From: Richard Henderson <richard.henderson@linaro.org>
To: qemu-devel@nongnu.org
Cc: Warner Losh <imp@bsdimp.com>
Subject: [PULL 12/15] common-user: Adjust system call return on FreeBSD
Date: Mon, 20 Dec 2021 12:24:57 -0800 [thread overview]
Message-ID: <20211220202500.111897-13-richard.henderson@linaro.org> (raw)
In-Reply-To: <20211220202500.111897-1-richard.henderson@linaro.org>
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>
---
common-user/host/aarch64/safe-syscall.inc.S | 14 +++++++++++++-
common-user/host/arm/safe-syscall.inc.S | 9 +++++++++
common-user/host/i386/safe-syscall.inc.S | 11 +++++++++++
common-user/host/x86_64/safe-syscall.inc.S | 11 +++++++++++
4 files changed, 44 insertions(+), 1 deletion(-)
diff --git a/common-user/host/aarch64/safe-syscall.inc.S b/common-user/host/aarch64/safe-syscall.inc.S
index 73a04b73b3..b8fd5b553e 100644
--- a/common-user/host/aarch64/safe-syscall.inc.S
+++ b/common-user/host/aarch64/safe-syscall.inc.S
@@ -60,17 +60,29 @@ safe_syscall_start:
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 66176a902c..bbfb89634e 100644
--- a/common-user/host/arm/safe-syscall.inc.S
+++ b/common-user/host/arm/safe-syscall.inc.S
@@ -74,10 +74,19 @@ safe_syscall_start:
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 aced8c5141..baf5400a29 100644
--- a/common-user/host/i386/safe-syscall.inc.S
+++ b/common-user/host/i386/safe-syscall.inc.S
@@ -71,9 +71,18 @@ safe_syscall_start:
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 @@ safe_syscall_end:
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 84fed206f9..a20927a783 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 @@ safe_syscall_start:
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 @@ safe_syscall_end:
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
--
2.25.1
next prev parent reply other threads:[~2021-12-20 20:34 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-20 20:24 [PULL 00/15] *-user: simplify safe signal handling Richard Henderson
2021-12-20 20:24 ` [PULL 01/15] linux-user: Untabify all safe-syscall.inc.S Richard Henderson
2021-12-20 20:24 ` [PULL 02/15] linux-user: Move syscall error detection into safe_syscall_base Richard Henderson
2022-01-04 13:51 ` Laurent Vivier
2022-01-04 18:12 ` Richard Henderson
2021-12-20 20:24 ` [PULL 03/15] linux-user/host/mips: Add safe-syscall.inc.S Richard Henderson
2021-12-20 20:24 ` [PULL 04/15] linux-user/host/sparc64: " Richard Henderson
2021-12-20 20:24 ` [PULL 05/15] linux-user: Remove HAVE_SAFE_SYSCALL and hostdep.h Richard Henderson
2021-12-20 20:24 ` [PULL 06/15] linux-user: Rename TARGET_ERESTARTSYS to QEMU_ERESTARTSYS Richard Henderson
2021-12-20 20:24 ` [PULL 07/15] bsd-user: " Richard Henderson
2021-12-20 20:24 ` [PULL 08/15] linux-user: Rename TARGET_QEMU_ESIGRETURN to QEMU_ESIGRETURN Richard Henderson
2021-12-20 20:24 ` [PULL 09/15] linux-user: Create special-errno.h Richard Henderson
2021-12-20 20:24 ` [PULL 10/15] bsd-user: " Richard Henderson
2021-12-20 20:24 ` [PULL 11/15] common-user: Move safe-syscall.* from linux-user Richard Henderson
2021-12-20 20:24 ` Richard Henderson [this message]
2021-12-20 20:24 ` [PULL 13/15] linux-user: Move thunk.c from top-level Richard Henderson
2021-12-20 20:24 ` [PULL 14/15] meson: Move linux_user_ss to linux-user/ Richard Henderson
2021-12-20 20:25 ` [PULL 15/15] meson: Move bsd_user_ss to bsd-user/ Richard Henderson
2021-12-20 23:54 ` [PULL 00/15] *-user: simplify safe signal handling Richard Henderson
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