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Commit 824122a3 authored by Maciej W. Rozycki's avatar Maciej W. Rozycki Committed by Ralf Baechle
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MIPS: DEC/SNI: O32 wrapper stack switching fixes 



Commit 231a35d3 [[MIPS] RM: Collected
changes] broke DECstation support by introducing an incompatible copy of
arch/mips/dec/prom/call_o32.S in arch/mips/fw/lib/, built unconditionally.
The copy happens to land earlier of the two among the modules used in the
link and is therefore chosen for the DECstation rather than the intended
original.  As a result random kernel data is corrupted because a pointer
to the "%s" formatted output template is used as a temporary stack pointer
rather than being passed down to prom_printf.  This also explains why
prom_printf still works, up to a point -- the next argument is the actual
string to output so it works just fine as the output template until enough
kernel data has been corrupted to cause a crash.

This change adjusts the modified wrapper in arch/mips/fw/lib/call_o32.S to
let callers request no stack switching by passing a null temporary stack
pointer in $a1, reworks the DECstation callers to work with the updated
interface and removes the old copy from arch/mips/dec/prom/call_o32.S.  A
few minor readability adjustments are included as well, most importantly
O32_SZREG is now used throughout where applicable rather than hardcoded
multiplies of 4 and $fp is used to access the argument save area as a more
usual register to operate the stack with rather than $s0.

Finally an update is made to the temporary stack space used by the SNI
platform to guarantee 8-byte alignment as per o32 requirements.

Signed-off-by: default avatarMaciej W. Rozycki <macro@linux-mips.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6668/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent af37530b

arch/mips/dec/prom/Makefile

+0 −1
Original line number Original line Diff line number Diff line
@@ -6,4 +6,3 @@ 
lib-y			+= init.o memory.o cmdline.o identify.o console.o

lib-y			+= init.o memory.o cmdline.o identify.o console.o





lib-$(CONFIG_32BIT)	+= locore.o
 
lib-$(CONFIG_32BIT)	+= locore.o
 
lib-$(CONFIG_64BIT)	+= call_o32.o

arch/mips/dec/prom/call_o32.S

deleted100644 → 0
+0 −89
Original line number Original line Diff line number Diff line 
/*

 *	O32 interface for the 64 (or N32) ABI.

 *

 *	Copyright (C) 2002  Maciej W. Rozycki

 *

 *	This program is free software; you can redistribute it and/or

 *	modify it under the terms of the GNU General Public License

 *	as published by the Free Software Foundation; either version

 *	2 of the License, or (at your option) any later version.

 */



#include <asm/asm.h>

#include <asm/regdef.h>



/* Maximum number of arguments supported.  Must be even!  */

#define O32_ARGC	32

/* Number of static registers we save.  */

#define O32_STATC	11

/* Frame size for both of the above.  */

#define O32_FRAMESZ	(4 * O32_ARGC + SZREG * O32_STATC)



		.text



/*

 * O32 function call dispatcher, for interfacing 32-bit ROM routines.

 *

 * The standard 64 (N32) calling sequence is supported, with a0

 * holding a function pointer, a1-a7 -- its first seven arguments

 * and the stack -- remaining ones (up to O32_ARGC, including a1-a7).

 * Static registers, gp and fp are preserved, v0 holds a result.

 * This code relies on the called o32 function for sp and ra

 * restoration and thus both this dispatcher and the current stack

 * have to be placed in a KSEGx (or KUSEG) address space.  Any

 * pointers passed have to point to addresses within one of these

 * spaces as well.

 */

NESTED(call_o32, O32_FRAMESZ, ra)

		REG_SUBU	sp,O32_FRAMESZ



		REG_S		ra,O32_FRAMESZ-1*SZREG(sp)

		REG_S		fp,O32_FRAMESZ-2*SZREG(sp)

		REG_S		gp,O32_FRAMESZ-3*SZREG(sp)

		REG_S		s7,O32_FRAMESZ-4*SZREG(sp)

		REG_S		s6,O32_FRAMESZ-5*SZREG(sp)

		REG_S		s5,O32_FRAMESZ-6*SZREG(sp)

		REG_S		s4,O32_FRAMESZ-7*SZREG(sp)

		REG_S		s3,O32_FRAMESZ-8*SZREG(sp)

		REG_S		s2,O32_FRAMESZ-9*SZREG(sp)

		REG_S		s1,O32_FRAMESZ-10*SZREG(sp)

		REG_S		s0,O32_FRAMESZ-11*SZREG(sp)



		move		jp,a0



		sll		a0,a1,zero

		sll		a1,a2,zero

		sll		a2,a3,zero

		sll		a3,a4,zero

		sw		a5,0x10(sp)

		sw		a6,0x14(sp)

		sw		a7,0x18(sp)



		PTR_LA		t0,O32_FRAMESZ(sp)

		PTR_LA		t1,0x1c(sp)

		li		t2,O32_ARGC-7

1:

		lw		t3,(t0)

		REG_ADDU	t0,SZREG

		sw		t3,(t1)

		REG_SUBU	t2,1

		REG_ADDU	t1,4

		bnez		t2,1b



		jalr		jp



		REG_L		s0,O32_FRAMESZ-11*SZREG(sp)

		REG_L		s1,O32_FRAMESZ-10*SZREG(sp)

		REG_L		s2,O32_FRAMESZ-9*SZREG(sp)

		REG_L		s3,O32_FRAMESZ-8*SZREG(sp)

		REG_L		s4,O32_FRAMESZ-7*SZREG(sp)

		REG_L		s5,O32_FRAMESZ-6*SZREG(sp)

		REG_L		s6,O32_FRAMESZ-5*SZREG(sp)

		REG_L		s7,O32_FRAMESZ-4*SZREG(sp)

		REG_L		gp,O32_FRAMESZ-3*SZREG(sp)

		REG_L		fp,O32_FRAMESZ-2*SZREG(sp)

		REG_L		ra,O32_FRAMESZ-1*SZREG(sp)



		REG_ADDU	sp,O32_FRAMESZ

		jr		ra

END(call_o32)

arch/mips/fw/lib/call_o32.S

+35 −22
Original line number Original line Diff line number Diff line 
/*

/*

 *	O32 interface for the 64 (or N32) ABI.

 *	O32 interface for the 64 (or N32) ABI.

 *

 *

 *	Copyright (C) 2002  Maciej W. Rozycki

 *	Copyright (C) 2002, 2014  Maciej W. Rozycki

 *

 *

 *	This program is free software; you can redistribute it and/or

 *	This program is free software; you can redistribute it and/or

 *	modify it under the terms of the GNU General Public License

 *	modify it under the terms of the GNU General Public License
@@ -12,28 +12,37 @@ 
#include <asm/asm.h>

#include <asm/asm.h>

#include <asm/regdef.h>

#include <asm/regdef.h>





/* O32 register size.  */

#define O32_SZREG	4

/* Maximum number of arguments supported.  Must be even!  */

/* Maximum number of arguments supported.  Must be even!  */

#define O32_ARGC	32

#define O32_ARGC	32

/* Number of static registers we save.  */

/* Number of static registers we save.  */

#define O32_STATC	11

#define O32_STATC	11

/* Frame size for static register  */

/* Argument area frame size.  */

#define O32_FRAMESZ	(SZREG * O32_STATC)

#define O32_ARGSZ	(O32_SZREG * O32_ARGC)

/* Frame size on new stack */

/* Static register save area frame size.  */

#define O32_FRAMESZ_NEW (SZREG + 4 * O32_ARGC)

#define O32_STATSZ	(SZREG * O32_STATC)

/* Stack pointer register save area frame size.  */

#define O32_SPSZ	SZREG

/* Combined area frame size.  */

#define O32_FRAMESZ	(O32_ARGSZ + O32_SPSZ + O32_STATSZ)

/* Switched stack frame size.  */

#define O32_NFRAMESZ	(O32_ARGSZ + O32_SPSZ)





		.text

		.text





/*

/*

 * O32 function call dispatcher, for interfacing 32-bit ROM routines.

 * O32 function call dispatcher, for interfacing 32-bit ROM routines.

 *

 *

 * The standard 64 (N32) calling sequence is supported, with a0

 * The standard 64 (N32) calling sequence is supported, with a0 holding

 * holding a function pointer, a1 a new stack pointer, a2-a7 -- its

 * a function pointer, a1 a pointer to the new stack to call the

 * first six arguments and the stack -- remaining ones (up to O32_ARGC,

 * function with or 0 if no stack switching is requested, a2-a7 -- the

 * including a2-a7). Static registers, gp and fp are preserved, v0 holds

 * function call's first six arguments, and the stack -- the remaining

 * a result. This code relies on the called o32 function for sp and ra

 * arguments (up to O32_ARGC, including a2-a7).  Static registers, gp

 * restoration and this dispatcher has to be placed in a KSEGx (or KUSEG)

 * and fp are preserved, v0 holds the result.  This code relies on the

 * address space.  Any pointers passed have to point to addresses within

 * called o32 function for sp and ra restoration and this dispatcher has

 * one of these spaces as well.

 * to be placed in a KSEGx (or KUSEG) address space.  Any pointers

 * passed have to point to addresses within one of these spaces as well.

 */

 */

NESTED(call_o32, O32_FRAMESZ, ra)

NESTED(call_o32, O32_FRAMESZ, ra)

		REG_SUBU	sp,O32_FRAMESZ

		REG_SUBU	sp,O32_FRAMESZ
@@ -51,32 +60,36 @@ NESTED(call_o32, O32_FRAMESZ, ra) 
		REG_S		s0,O32_FRAMESZ-11*SZREG(sp)

		REG_S		s0,O32_FRAMESZ-11*SZREG(sp)





		move		jp,a0

		move		jp,a0

		REG_SUBU	s0,a1,O32_FRAMESZ_NEW



		REG_S		sp,O32_FRAMESZ_NEW-1*SZREG(s0)

		move		fp,sp

		beqz		a1,0f

		REG_SUBU	fp,a1,O32_NFRAMESZ

0:

		REG_S		sp,O32_NFRAMESZ-1*SZREG(fp)





		sll		a0,a2,zero

		sll		a0,a2,zero

		sll		a1,a3,zero

		sll		a1,a3,zero

		sll		a2,a4,zero

		sll		a2,a4,zero

		sll		a3,a5,zero

		sll		a3,a5,zero

		sw		a6,0x10(s0)

		sw		a6,4*O32_SZREG(fp)

		sw		a7,0x14(s0)

		sw		a7,5*O32_SZREG(fp)





		PTR_LA		t0,O32_FRAMESZ(sp)

		PTR_LA		t0,O32_FRAMESZ(sp)

		PTR_LA		t1,0x18(s0)

		PTR_LA		t1,6*O32_SZREG(fp)

		li		t2,O32_ARGC-6

		li		t2,O32_ARGC-6

1:

1:

		lw		t3,(t0)

		lw		t3,(t0)

		REG_ADDU	t0,SZREG

		REG_ADDU	t0,SZREG

		sw		t3,(t1)

		sw		t3,(t1)

		REG_SUBU	t2,1

		REG_SUBU	t2,1

		REG_ADDU	t1,4

		REG_ADDU	t1,O32_SZREG

		bnez		t2,1b

		bnez		t2,1b





		move		sp,s0

		move		sp,fp





		jalr		jp

		jalr		jp





		REG_L		sp,O32_FRAMESZ_NEW-1*SZREG(sp)

		REG_L		sp,O32_NFRAMESZ-1*SZREG(sp)





		REG_L		s0,O32_FRAMESZ-11*SZREG(sp)

		REG_L		s0,O32_FRAMESZ-11*SZREG(sp)

		REG_L		s1,O32_FRAMESZ-10*SZREG(sp)

		REG_L		s1,O32_FRAMESZ-10*SZREG(sp)

arch/mips/fw/sni/sniprom.c

+2 −1
Original line number Original line Diff line number Diff line
@@ -40,7 +40,8 @@ 




#ifdef CONFIG_64BIT

#ifdef CONFIG_64BIT





static u8 o32_stk[16384];

/* O32 stack has to be 8-byte aligned. */

static u64 o32_stk[4096];

#define O32_STK	  &o32_stk[sizeof(o32_stk)]

#define O32_STK	  &o32_stk[sizeof(o32_stk)]





#define __PROM_O32(fun, arg) fun arg __asm__(#fun); \

#define __PROM_O32(fun, arg) fun arg __asm__(#fun); \

arch/mips/include/asm/dec/prom.h

+24 −24
Original line number Original line Diff line number Diff line
@@ -113,31 +113,31 @@ extern int (*__pmax_close)(int); 
#define __DEC_PROM_O32(fun, arg) fun arg __asm__(#fun); \

#define __DEC_PROM_O32(fun, arg) fun arg __asm__(#fun); \

				 __asm__(#fun " = call_o32")

				 __asm__(#fun " = call_o32")





int __DEC_PROM_O32(_rex_bootinit, (int (*)(void)));

int __DEC_PROM_O32(_rex_bootinit, (int (*)(void), void *));

int __DEC_PROM_O32(_rex_bootread, (int (*)(void)));

int __DEC_PROM_O32(_rex_bootread, (int (*)(void), void *));

int __DEC_PROM_O32(_rex_getbitmap, (int (*)(memmap *), memmap *));

int __DEC_PROM_O32(_rex_getbitmap, (int (*)(memmap *), void *, memmap *));

unsigned long *__DEC_PROM_O32(_rex_slot_address,

unsigned long *__DEC_PROM_O32(_rex_slot_address,

			     (unsigned long *(*)(int), int));

			     (unsigned long *(*)(int), void *, int));

void *__DEC_PROM_O32(_rex_gettcinfo, (void *(*)(void)));

void *__DEC_PROM_O32(_rex_gettcinfo, (void *(*)(void), void *));

int __DEC_PROM_O32(_rex_getsysid, (int (*)(void)));

int __DEC_PROM_O32(_rex_getsysid, (int (*)(void), void *));

void __DEC_PROM_O32(_rex_clear_cache, (void (*)(void)));

void __DEC_PROM_O32(_rex_clear_cache, (void (*)(void), void *));





int __DEC_PROM_O32(_prom_getchar, (int (*)(void)));

int __DEC_PROM_O32(_prom_getchar, (int (*)(void), void *));

char *__DEC_PROM_O32(_prom_getenv, (char *(*)(char *), char *));

char *__DEC_PROM_O32(_prom_getenv, (char *(*)(char *), void *, char *));

int __DEC_PROM_O32(_prom_printf, (int (*)(char *, ...), char *, ...));

int __DEC_PROM_O32(_prom_printf, (int (*)(char *, ...), void *, char *, ...));









#define rex_bootinit()		_rex_bootinit(__rex_bootinit)

#define rex_bootinit()		_rex_bootinit(__rex_bootinit, NULL)

#define rex_bootread()		_rex_bootread(__rex_bootread)

#define rex_bootread()		_rex_bootread(__rex_bootread, NULL)

#define rex_getbitmap(x)	_rex_getbitmap(__rex_getbitmap, x)

#define rex_getbitmap(x)	_rex_getbitmap(__rex_getbitmap, NULL, x)

#define rex_slot_address(x)	_rex_slot_address(__rex_slot_address, x)

#define rex_slot_address(x)	_rex_slot_address(__rex_slot_address, NULL, x)

#define rex_gettcinfo()		_rex_gettcinfo(__rex_gettcinfo)

#define rex_gettcinfo()		_rex_gettcinfo(__rex_gettcinfo, NULL)

#define rex_getsysid()		_rex_getsysid(__rex_getsysid)

#define rex_getsysid()		_rex_getsysid(__rex_getsysid, NULL)

#define rex_clear_cache()	_rex_clear_cache(__rex_clear_cache)

#define rex_clear_cache()	_rex_clear_cache(__rex_clear_cache, NULL)





#define prom_getchar()		_prom_getchar(__prom_getchar)

#define prom_getchar()		_prom_getchar(__prom_getchar, NULL)

#define prom_getenv(x)		_prom_getenv(__prom_getenv, x)

#define prom_getenv(x)		_prom_getenv(__prom_getenv, NULL, x)

#define prom_printf(x...)	_prom_printf(__prom_printf, x)

#define prom_printf(x...)	_prom_printf(__prom_printf, NULL, x)





#else /* !CONFIG_64BIT */

#else /* !CONFIG_64BIT */