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xtensa: deprecate fast_xtensa and fast_spill_registers syscalls

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These syscalls are not used by userspace tools for some time now, and
they have issues when called with invalid arguments. It's not worth
changing signal delivery mechanism as we don't expect any new users for
these syscalls. Let's keep them for backwards compatibility under #ifdef,
disabled by default.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
This commit is contained in:
Max Filippov 2014-08-07 03:32:30 +04:00
parent 3cfc096e4c
commit 9184289c97
2 changed files with 54 additions and 0 deletions
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26
arch/xtensa/Kconfig
View File

@ -238,6 +238,32 @@ config HIGHMEM
If unsure, say Y.
config FAST_SYSCALL_XTENSA
bool "Enable fast atomic syscalls"
default n
help
fast_syscall_xtensa is a syscall that can make atomic operations
on UP kernel when processor has no s32c1i support.
This syscall is deprecated. It may have issues when called with
invalid arguments. It is provided only for backwards compatibility.
Only enable it if your userspace software requires it.
If unsure, say N.
config FAST_SYSCALL_SPILL_REGISTERS
bool "Enable spill registers syscall"
default n
help
fast_syscall_spill_registers is a syscall that spills all active
register windows of a calling userspace task onto its stack.
This syscall is deprecated. It may have issues when called with
invalid arguments. It is provided only for backwards compatibility.
Only enable it if your userspace software requires it.
If unsure, say N.
endmenu
config XTENSA_CALIBRATE_CCOUNT

28
arch/xtensa/kernel/entry.S
View File

@ -986,6 +986,8 @@ ENDPROC(fast_syscall_unrecoverable)
* j done
*/
#ifdef CONFIG_FAST_SYSCALL_XTENSA
#define TRY \
.section __ex_table, "a"; \
.word 66f, 67f; \
@ -1049,6 +1051,18 @@ CATCH
ENDPROC(fast_syscall_xtensa)
#else /* CONFIG_FAST_SYSCALL_XTENSA */
ENTRY(fast_syscall_xtensa)
l32i a0, a2, PT_AREG0 # restore a0
movi a2, -ENOSYS
rfe
ENDPROC(fast_syscall_xtensa)
#endif /* CONFIG_FAST_SYSCALL_XTENSA */
/* fast_syscall_spill_registers.
*
@ -1064,6 +1078,8 @@ ENDPROC(fast_syscall_xtensa)
* Note: We assume the stack pointer is EXC_TABLE_KSTK in the fixup handler.
*/
#ifdef CONFIG_FAST_SYSCALL_SPILL_REGISTERS
ENTRY(fast_syscall_spill_registers)
/* Register a FIXUP handler (pass current wb as a parameter) */
@ -1398,6 +1414,18 @@ ENTRY(fast_syscall_spill_registers_fixup_return)
ENDPROC(fast_syscall_spill_registers_fixup_return)
#else /* CONFIG_FAST_SYSCALL_SPILL_REGISTERS */
ENTRY(fast_syscall_spill_registers)
l32i a0, a2, PT_AREG0 # restore a0
movi a2, -ENOSYS
rfe
ENDPROC(fast_syscall_spill_registers)
#endif /* CONFIG_FAST_SYSCALL_SPILL_REGISTERS */
#ifdef CONFIG_MMU
/*
* We should never get here. Bail out!