From 5bfd125ec8ba8aab04f3a636dcea39f6c4075ced Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Tue, 23 Nov 2021 15:18:49 +0100 Subject: 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 Signed-off-by: Richard Henderson --- 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(-) (limited to 'common-user') 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 -- cgit v1.2.3