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authorLinus Torvalds <torvalds@linux-foundation.org>2009-04-03 09:52:04 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-04-03 09:52:04 -0700
commit3ba113d14cedcd88105a3b9c90f8ecce829e1095 (patch)
tree357f50c6a45bf57a16d46b3157dfcd4e28233079 /arch/parisc/kernel/syscall.S
parentbad6a5c08c119572c888d5df2bd7691a4da6b9e8 (diff)
parentb609308e1415efebdf79ebd553f4dd47b0ff2722 (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/kyle/parisc-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/kyle/parisc-2.6: (23 commits) parisc: move dereference_function_descriptor to process.c parisc: Move kernel Elf_Fdesc define to <asm/elf.h> parisc: fix build when ARCH_HAS_KMAP parisc: fix "make tar-pkg" parisc: drivers: fix warnings parisc: select BUG always parisc: asm/pdc.h should include asm/page.h parisc: led: remove proc_dir_entry::owner parisc: fix macro expansion in atomic.h parisc: iosapic: fix build breakage parisc: oops_enter()/oops_exit() in die() parisc: document light weight syscall ABI parisc: blink all or loadavg LEDs on oops parisc: add ftrace (function and graph tracer) functionality parisc: simplify sys_clone() parisc: add LATENCYTOP_SUPPORT and CONFIG_STACKTRACE_SUPPORT parisc: allow to build with 16k default kernel page size parisc: expose 32/64-bit capabilities in cpuinfo parisc: use constants instead of numbers in assembly parisc: fix usage of 32bit PTE page table entries on 32bit kernels ...
Diffstat (limited to 'arch/parisc/kernel/syscall.S')
-rw-r--r--arch/parisc/kernel/syscall.S58
1 files changed, 48 insertions, 10 deletions
diff --git a/arch/parisc/kernel/syscall.S b/arch/parisc/kernel/syscall.S
index 69b6eebc466..59fc1a43ec3 100644
--- a/arch/parisc/kernel/syscall.S
+++ b/arch/parisc/kernel/syscall.S
@@ -365,17 +365,51 @@ tracesys_sigexit:
/*********************************************************
- Light-weight-syscall code
+ 32/64-bit Light-Weight-Syscall ABI
- r20 - lws number
- r26,r25,r24,r23,r22 - Input registers
- r28 - Function return register
- r21 - Error code.
+ * - Indicates a hint for userspace inline asm
+ implementations.
- Scracth: Any of the above that aren't being
- currently used, including r1.
+ Syscall number (caller-saves)
+ - %r20
+ * In asm clobber.
- Return pointer: r31 (Not usable)
+ Argument registers (caller-saves)
+ - %r26, %r25, %r24, %r23, %r22
+ * In asm input.
+
+ Return registers (caller-saves)
+ - %r28 (return), %r21 (errno)
+ * In asm output.
+
+ Caller-saves registers
+ - %r1, %r27, %r29
+ - %r2 (return pointer)
+ - %r31 (ble link register)
+ * In asm clobber.
+
+ Callee-saves registers
+ - %r3-%r18
+ - %r30 (stack pointer)
+ * Not in asm clobber.
+
+ If userspace is 32-bit:
+ Callee-saves registers
+ - %r19 (32-bit PIC register)
+
+ Differences from 32-bit calling convention:
+ - Syscall number in %r20
+ - Additional argument register %r22 (arg4)
+ - Callee-saves %r19.
+
+ If userspace is 64-bit:
+ Callee-saves registers
+ - %r27 (64-bit PIC register)
+
+ Differences from 64-bit calling convention:
+ - Syscall number in %r20
+ - Additional argument register %r22 (arg4)
+ - Callee-saves %r27.
Error codes returned by entry path:
@@ -473,7 +507,8 @@ lws_compare_and_swap64:
b,n lws_compare_and_swap
#else
/* If we are not a 64-bit kernel, then we don't
- * implement having 64-bit input registers
+ * have 64-bit input registers, and calling
+ * the 64-bit LWS CAS returns ENOSYS.
*/
b,n lws_exit_nosys
#endif
@@ -635,12 +670,15 @@ END(sys_call_table64)
/*
All light-weight-syscall atomic operations
will use this set of locks
+
+ NOTE: The lws_lock_start symbol must be
+ at least 16-byte aligned for safe use
+ with ldcw.
*/
.section .data
.align PAGE_SIZE
ENTRY(lws_lock_start)
/* lws locks */
- .align 16
.rept 16
/* Keep locks aligned at 16-bytes */
.word 1