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Commit 40138249 authored by Al Viro's avatar Al Viro Committed by David S. Miller
Browse files

sparc64: Rearrange thread info to cheaply clear syscall noerror state. 



After fixing a couple of brainos, it even seems to work.  What's done here
is move of ->syscall_noerror right before FPDEPTH byte in ->flags and
using sth to [%g6 + TI_SYS_NOERROR] instead of stb to [%g6 + TI_FPDEPTH] in
both branches of etrap_save.  AFAICS, that ought to be solid.  Again,
deciding what to do with now unused delay slot of branch on ->syscall_noerror
and dealing with the order of tests in ret_from_sys is a separate question,
but at least that way we don't have to clean ->syscall_noerror in there at
all.  AFAICS, it ought to be a clear win - sth is not going to cost more than
stb on etrap_64.S side of things, and we are losing write on syscalls.S one.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ecefbd94

arch/sparc/include/asm/ptrace.h

+1 −3
Original line number Diff line number Diff line
@@ -202,9 +202,7 @@ struct global_reg_snapshot { 
};

extern struct global_reg_snapshot global_reg_snapshot[NR_CPUS];



#define force_successful_syscall_return()	    \

do {	current_thread_info()->syscall_noerror = 1; \

} while (0)

#define force_successful_syscall_return() set_thread_noerror(1)

#define user_mode(regs) (!((regs)->tstate & TSTATE_PRIV))

#define instruction_pointer(regs) ((regs)->tpc)

#define instruction_pointer_set(regs, val) ((regs)->tpc = (val))

arch/sparc/include/asm/thread_info_64.h

+10 −6
Original line number Diff line number Diff line
@@ -18,10 +18,12 @@ 
#define TI_FLAG_CWP_SHIFT		40

#define TI_FLAG_BYTE_CURRENT_DS		3

#define TI_FLAG_CURRENT_DS_SHIFT	32

#define TI_FLAG_BYTE_FPDEPTH		4

#define TI_FLAG_FPDEPTH_SHIFT		24

#define TI_FLAG_BYTE_WSAVED		5

#define TI_FLAG_WSAVED_SHIFT		16

#define TI_FLAG_BYTE_NOERROR		4

#define TI_FLAG_BYTE_NOERROR_SHIFT	24

#define TI_FLAG_BYTE_FPDEPTH		5

#define TI_FLAG_FPDEPTH_SHIFT		16

#define TI_FLAG_BYTE_WSAVED		6

#define TI_FLAG_WSAVED_SHIFT		8



#include <asm/page.h>
@@ -47,7 +49,7 @@ struct thread_info { 
	struct exec_domain	*exec_domain;

	int			preempt_count;	/* 0 => preemptable, <0 => BUG */

	__u8			new_child;

	__u8			syscall_noerror;

	__u8			__pad;

	__u16			cpu;



	unsigned long		*utraps;
@@ -77,6 +79,7 @@ struct thread_info { 
#define TI_CURRENT_DS	(TI_FLAGS + TI_FLAG_BYTE_CURRENT_DS)

#define TI_FPDEPTH	(TI_FLAGS + TI_FLAG_BYTE_FPDEPTH)

#define TI_WSAVED	(TI_FLAGS + TI_FLAG_BYTE_WSAVED)

#define TI_SYS_NOERROR	(TI_FLAGS + TI_FLAG_BYTE_NOERROR)

#define TI_FPSAVED	0x00000010

#define TI_KSP		0x00000018

#define TI_FAULT_ADDR	0x00000020
@@ -84,7 +87,6 @@ struct thread_info { 
#define TI_EXEC_DOMAIN	0x00000030

#define TI_PRE_COUNT	0x00000038

#define TI_NEW_CHILD	0x0000003c

#define TI_SYS_NOERROR	0x0000003d

#define TI_CPU		0x0000003e

#define TI_UTRAPS	0x00000040

#define TI_REG_WINDOW	0x00000048
@@ -155,6 +157,8 @@ register struct thread_info *current_thread_info_reg asm("g6"); 
#define set_thread_cwp(val)		(__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_CWP] = (val))

#define get_thread_current_ds()		(__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_CURRENT_DS])

#define set_thread_current_ds(val)	(__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_CURRENT_DS] = (val))

#define get_thread_noerror()		(__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_NOERROR])

#define set_thread_noerror(val)		(__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_NOERROR] = (val))

#define get_thread_fpdepth()		(__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_FPDEPTH])

#define set_thread_fpdepth(val)		(__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_FPDEPTH] = (val))

#define get_thread_wsaved()		(__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_WSAVED])

arch/sparc/kernel/etrap_64.S

+6 −2
Original line number Diff line number Diff line
@@ -92,8 +92,10 @@ etrap_save: save %g2, -STACK_BIAS, %sp 
		rdpr	%wstate, %g2

		wrpr	%g0, 0, %canrestore

		sll	%g2, 3, %g2



		/* Set TI_SYS_FPDEPTH to 1 and clear TI_SYS_NOERROR.  */

		mov	1, %l5

		stb	%l5, [%l6 + TI_FPDEPTH]

		sth	%l5, [%l6 + TI_SYS_NOERROR]



		wrpr	%g3, 0, %otherwin

		wrpr	%g2, 0, %wstate
@@ -152,7 +154,9 @@ etrap_save: save %g2, -STACK_BIAS, %sp 
		add	%l6, TI_FPSAVED + 1, %l4

		srl	%l5, 1, %l3

		add	%l5, 2, %l5

		stb	%l5, [%l6 + TI_FPDEPTH]



		/* Set TI_SYS_FPDEPTH to %l5 and clear TI_SYS_NOERROR.  */

		sth	%l5, [%l6 + TI_SYS_NOERROR]

		ba,pt	%xcc, 2b

		 stb	%g0, [%l4 + %l3]

		nop

arch/sparc/kernel/syscalls.S

+2 −2
Original line number Diff line number Diff line
@@ -221,8 +221,8 @@ ret_sys_call: 
	 * was invoked.

	 */

	ldub	[%g6 + TI_SYS_NOERROR], %l2

	brnz,a,pn %l2, 80f

	 stb	%g0, [%g6 + TI_SYS_NOERROR]

	brnz,pn %l2, 80f

	 nop



	cmp	%o0, -ERESTART_RESTARTBLOCK

	bgeu,pn	%xcc, 1f

arch/sparc/kernel/traps_64.c

+0 −2
Original line number Diff line number Diff line
@@ -2547,8 +2547,6 @@ void __init trap_init(void) 
		     TI_PRE_COUNT != offsetof(struct thread_info,

					      preempt_count) ||

		     TI_NEW_CHILD != offsetof(struct thread_info, new_child) ||

		     TI_SYS_NOERROR != offsetof(struct thread_info,

						syscall_noerror) ||

		     TI_RESTART_BLOCK != offsetof(struct thread_info,

						  restart_block) ||

		     TI_KUNA_REGS != offsetof(struct thread_info,