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From: Warner Losh <imp@bsdimp.com>
To: qemu-devel@nongnu.org
Cc: Richard Henderson <richard.henderson@linaro.org>,
	Laurent Vivier <laurent@vivier.eu>, Warner Losh <imp@bsdimp.com>,
	Philippe Mathieu-Daude <f4bug@amsat.org>
Subject: [RFC 4/4] common-user: Allow return codes to be adjusted after sytsem call
Date: Sun,  7 Nov 2021 19:37:38 -0700	[thread overview]
Message-ID: <20211108023738.42125-5-imp@bsdimp.com> (raw)
In-Reply-To: <20211108023738.42125-1-imp@bsdimp.com>

All the *-users generally use the Linux style of negative return codes
for errno. However, other systems, like FreeBSD, have a different
convention. Allow those systems to insert code after the syscall that
adjusts the return value of the system call to match the native linux
format.

Signed-off-by: Warner Losh <imp@bsdimp.com>
---
 common-user/host/aarch64/safe-syscall.inc.S | 1 +
 common-user/host/arm/safe-syscall.inc.S     | 1 +
 common-user/host/i386/safe-syscall.inc.S    | 1 +
 common-user/host/ppc64/safe-syscall.inc.S   | 1 +
 common-user/host/riscv/safe-syscall.inc.S   | 1 +
 common-user/host/s390x/safe-syscall.inc.S   | 1 +
 common-user/host/x86_64/safe-syscall.inc.S  | 1 +
 linux-user/safe-syscall.S                   | 1 +
 8 files changed, 8 insertions(+)

diff --git a/common-user/host/aarch64/safe-syscall.inc.S b/common-user/host/aarch64/safe-syscall.inc.S
index bc1f5a9792..81d83e8e79 100644
--- a/common-user/host/aarch64/safe-syscall.inc.S
+++ b/common-user/host/aarch64/safe-syscall.inc.S
@@ -64,6 +64,7 @@ safe_syscall_start:
 	svc	0x0
 safe_syscall_end:
 	/* code path for having successfully executed the syscall */
+	ADJUST_SYSCALL_RETCODE
 	ret
 
 0:
diff --git a/common-user/host/arm/safe-syscall.inc.S b/common-user/host/arm/safe-syscall.inc.S
index 88c4958504..40e9a5e28d 100644
--- a/common-user/host/arm/safe-syscall.inc.S
+++ b/common-user/host/arm/safe-syscall.inc.S
@@ -78,6 +78,7 @@ safe_syscall_start:
 	swi	0
 safe_syscall_end:
 	/* code path for having successfully executed the syscall */
+	ADJUST_SYSCALL_RETCODE
 	pop	{ r4, r5, r6, r7, r8, pc }
 
 1:
diff --git a/common-user/host/i386/safe-syscall.inc.S b/common-user/host/i386/safe-syscall.inc.S
index 9e58fc6504..eb6b43bd81 100644
--- a/common-user/host/i386/safe-syscall.inc.S
+++ b/common-user/host/i386/safe-syscall.inc.S
@@ -75,6 +75,7 @@ safe_syscall_start:
 	int	$0x80
 safe_syscall_end:
 	/* code path for having successfully executed the syscall */
+	ADJUST_SYSCALL_RETCODE
 	pop	%ebx
 	.cfi_remember_state
 	.cfi_adjust_cfa_offset -4
diff --git a/common-user/host/ppc64/safe-syscall.inc.S b/common-user/host/ppc64/safe-syscall.inc.S
index 875133173b..974bd03f8d 100644
--- a/common-user/host/ppc64/safe-syscall.inc.S
+++ b/common-user/host/ppc64/safe-syscall.inc.S
@@ -75,6 +75,7 @@ safe_syscall_start:
 	sc
 safe_syscall_end:
 	/* code path when we did execute the syscall */
+	ADJUST_SYSCALL_RETCODE
 	ld 14, 16(1) /* restore r14 to its original value */
 	bnslr+
 
diff --git a/common-user/host/riscv/safe-syscall.inc.S b/common-user/host/riscv/safe-syscall.inc.S
index 9ca3fbfd1e..a4bd5c5c72 100644
--- a/common-user/host/riscv/safe-syscall.inc.S
+++ b/common-user/host/riscv/safe-syscall.inc.S
@@ -66,6 +66,7 @@ safe_syscall_start:
 	scall
 safe_syscall_end:
 	/* code path for having successfully executed the syscall */
+	ADJUST_SYSCALL_RETCODE
 	ret
 
 0:
diff --git a/common-user/host/s390x/safe-syscall.inc.S b/common-user/host/s390x/safe-syscall.inc.S
index 414b44ad38..4ba60fbed0 100644
--- a/common-user/host/s390x/safe-syscall.inc.S
+++ b/common-user/host/s390x/safe-syscall.inc.S
@@ -76,6 +76,7 @@ safe_syscall_start:
 	jne	2f
 	svc	0
 safe_syscall_end:
+	ADJUST_SYSCALL_RETCODE
 
 1:	lg	%r15,0(%r15)		/* load back chain */
 	.cfi_remember_state
diff --git a/common-user/host/x86_64/safe-syscall.inc.S b/common-user/host/x86_64/safe-syscall.inc.S
index f36992daa3..e1ae6f83e6 100644
--- a/common-user/host/x86_64/safe-syscall.inc.S
+++ b/common-user/host/x86_64/safe-syscall.inc.S
@@ -72,6 +72,7 @@ safe_syscall_start:
         syscall
 safe_syscall_end:
         /* code path for having successfully executed the syscall */
+	ADJUST_SYSCALL_RETCODE
         pop     %rbp
         .cfi_remember_state
         .cfi_def_cfa_offset 8
diff --git a/linux-user/safe-syscall.S b/linux-user/safe-syscall.S
index 42ea7c40ba..0d6dd19398 100644
--- a/linux-user/safe-syscall.S
+++ b/linux-user/safe-syscall.S
@@ -17,6 +17,7 @@
  * so that this will pull in the right fragment for the architecture.
  */
 #ifdef HAVE_SAFE_SYSCALL
+#define ADJUST_SYSCALL_RETCODE		/* No adjustment for linux */
 #include "safe-syscall.inc.S"
 #endif
 
-- 
2.33.0



  parent reply	other threads:[~2021-11-08  2:48 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-08  2:37 [RFC 0/4] linux-user: simplify safe signal handling Warner Losh
2021-11-08  2:37 ` [RFC 1/4] linux-user: Add host_signal_set_pc to set pc in mcontext Warner Losh
2021-11-08 15:03   ` Richard Henderson
2021-11-10 15:43   ` Philippe Mathieu-Daudé
2021-11-08  2:37 ` [RFC 2/4] linux-user/signal.c: Create a common rewind_if_in_safe_syscall Warner Losh
2021-11-08 15:07   ` Richard Henderson
2021-11-08 16:39     ` Warner Losh
2021-11-10 16:20       ` Warner Losh
2021-11-10 16:31         ` Richard Henderson
2021-11-10 15:44   ` Philippe Mathieu-Daudé
2021-11-08  2:37 ` [RFC 3/4] linux-user/safe-syscall.inc.S: Move to common-user Warner Losh
2021-11-08  2:37 ` Warner Losh [this message]
2021-11-08 15:10   ` [RFC 4/4] common-user: Allow return codes to be adjusted after sytsem call Richard Henderson
2021-11-08 18:49     ` Warner Losh
2021-11-09  8:11       ` Richard Henderson
2021-11-10  2:10         ` Warner Losh

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