[PATCH v2 2/2] syscall.2: add x32 ABI

From: Jann Horn
Date: Tue Mar 24 2015 - 14:40:51 EST


[added H. Peter Anvin to CC for this patch because he
seems to have contributed large parts of the X32 code]

---
man2/syscall.2 | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/man2/syscall.2 b/man2/syscall.2
index ef8f3cf..1f25255 100644
--- a/man2/syscall.2
+++ b/man2/syscall.2
@@ -170,12 +170,18 @@ s390 svc 0 r1 r2 See below
s390x svc 0 r1 r2 See below
sparc/32 t 0x10 g1 o0
sparc/64 t 0x6d g1 o0
-x86_64 syscall rax rax
+x86_64 syscall rax rax See below
+x32 syscall rax rax See below
.TE
.PP
For s390 and s390x, NR (the system call number)
may be passed directly with "svc NR" if it is less than 256.

+The x32 ABI uses the same instruction as the x86_64 ABI and is used on
+the same processors. To differentiate between them, the bitmask
+.I __X32_SYSCALL_BIT
+is bitwise-ORed into the syscall number for syscalls under the x32 ABI.
+
On a few architectures,
a register is used to indicate simple boolean failure of the system call:
ia64 uses
@@ -210,6 +216,7 @@ s390x r2 r3 r4 r5 r6 r7 -
sparc/32 o0 o1 o2 o3 o4 o5 -
sparc/64 o0 o1 o2 o3 o4 o5 -
x86_64 rdi rsi rdx r10 r8 r9 -
+x32 rdi rsi rdx r10 r8 r9 -
.TE
.PP
The mips/o32 system call convention passes
--
2.1.4
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