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Commit 9184289c authored by Max Filippov's avatar Max Filippov
Browse files

xtensa: deprecate fast_xtensa and fast_spill_registers syscalls 



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: default avatarMax Filippov <jcmvbkbc@gmail.com>
parent 3cfc096e

arch/xtensa/Kconfig

+26 −0
Original line number Diff line number Diff line
@@ -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

arch/xtensa/kernel/entry.S

+28 −0
Original line number Diff line number Diff line
@@ -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!