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linux/arch/powerpc/kernel/entry_64.S
Paul Mackerras 3eb6f26bcd powerpc: correct register usage in 64-bit syscall exit path 
Since we don't restore the volatile registers in the syscall exit
path, we need to make sure we don't leak any potentially interesting
values from the kernel to userspace.  This was already the case for
all except r11.  This makes it use r11 for an MSR value, so r11 will
have an (uninteresting) MSR value in it on return to userspace.

Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-12-20 15:38:47 +11:00

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/*
* arch/ppc64/kernel/entry.S
*
* PowerPC version
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
* Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP
* Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu>
* Adapted for Power Macintosh by Paul Mackerras.
* Low-level exception handlers and MMU support
* rewritten by Paul Mackerras.
* Copyright (C) 1996 Paul Mackerras.
* MPC8xx modifications Copyright (C) 1997 Dan Malek (dmalek@jlc.net).
*
* This file contains the system call entry code, context switch
* code, and exception/interrupt return code for PowerPC.
*
* 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 <linux/config.h>
#include <linux/errno.h>
#include <asm/unistd.h>
#include <asm/processor.h>
#include <asm/page.h>
#include <asm/mmu.h>
#include <asm/thread_info.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#include <asm/cputable.h>
#ifdef CONFIG_PPC_ISERIES
#define DO_SOFT_DISABLE
#endif
/*
* System calls.
*/
.section ".toc","aw"
.SYS_CALL_TABLE:
.tc .sys_call_table[TC],.sys_call_table
/* This value is used to mark exception frames on the stack. */
exception_marker:
.tc ID_72656773_68657265[TC],0x7265677368657265
.section ".text"
.align 7
#undef SHOW_SYSCALLS
.globl system_call_common
system_call_common:
andi. r10,r12,MSR_PR
mr r10,r1
addi r1,r1,-INT_FRAME_SIZE
beq- 1f
ld r1,PACAKSAVE(r13)
1: std r10,0(r1)
std r11,_NIP(r1)
std r12,_MSR(r1)
std r0,GPR0(r1)
std r10,GPR1(r1)
std r2,GPR2(r1)
std r3,GPR3(r1)
std r4,GPR4(r1)
std r5,GPR5(r1)
std r6,GPR6(r1)
std r7,GPR7(r1)
std r8,GPR8(r1)
li r11,0
std r11,GPR9(r1)
std r11,GPR10(r1)
std r11,GPR11(r1)
std r11,GPR12(r1)
std r9,GPR13(r1)
crclr so
mfcr r9
mflr r10
li r11,0xc01
std r9,_CCR(r1)
std r10,_LINK(r1)
std r11,_TRAP(r1)
mfxer r9
mfctr r10
std r9,_XER(r1)
std r10,_CTR(r1)
std r3,ORIG_GPR3(r1)
ld r2,PACATOC(r13)
addi r9,r1,STACK_FRAME_OVERHEAD
ld r11,exception_marker@toc(r2)
std r11,-16(r9) /* "regshere" marker */
#ifdef CONFIG_PPC_ISERIES
/* Hack for handling interrupts when soft-enabling on iSeries */
cmpdi cr1,r0,0x5555 /* syscall 0x5555 */
andi. r10,r12,MSR_PR /* from kernel */
crand 4*cr0+eq,4*cr1+eq,4*cr0+eq
beq hardware_interrupt_entry
lbz r10,PACAPROCENABLED(r13)
std r10,SOFTE(r1)
#endif
mfmsr r11
ori r11,r11,MSR_EE
mtmsrd r11,1
#ifdef SHOW_SYSCALLS
bl .do_show_syscall
REST_GPR(0,r1)
REST_4GPRS(3,r1)
REST_2GPRS(7,r1)
addi r9,r1,STACK_FRAME_OVERHEAD
#endif
clrrdi r11,r1,THREAD_SHIFT
li r12,0
ld r10,TI_FLAGS(r11)
stb r12,TI_SC_NOERR(r11)
andi. r11,r10,_TIF_SYSCALL_T_OR_A
bne- syscall_dotrace
syscall_dotrace_cont:
cmpldi 0,r0,NR_syscalls
bge- syscall_enosys
system_call: /* label this so stack traces look sane */
/*
* Need to vector to 32 Bit or default sys_call_table here,
* based on caller's run-mode / personality.
*/
ld r11,.SYS_CALL_TABLE@toc(2)
andi. r10,r10,_TIF_32BIT
beq 15f
addi r11,r11,8 /* use 32-bit syscall entries */
clrldi r3,r3,32
clrldi r4,r4,32
clrldi r5,r5,32
clrldi r6,r6,32
clrldi r7,r7,32
clrldi r8,r8,32
15:
slwi r0,r0,4
ldx r10,r11,r0 /* Fetch system call handler [ptr] */
mtctr r10
bctrl /* Call handler */
syscall_exit:
#ifdef SHOW_SYSCALLS
std r3,GPR3(r1)
bl .do_show_syscall_exit
ld r3,GPR3(r1)
#endif
std r3,RESULT(r1)
ld r5,_CCR(r1)
li r10,-_LAST_ERRNO
cmpld r3,r10
clrrdi r12,r1,THREAD_SHIFT
bge- syscall_error
syscall_error_cont:
/* check for syscall tracing or audit */
ld r9,TI_FLAGS(r12)
andi. r0,r9,(_TIF_SYSCALL_T_OR_A|_TIF_SINGLESTEP)
bne- syscall_exit_trace
syscall_exit_trace_cont:
/* disable interrupts so current_thread_info()->flags can't change,
and so that we don't get interrupted after loading SRR0/1. */
ld r8,_MSR(r1)
andi. r10,r8,MSR_RI
beq- unrecov_restore
mfmsr r10
rldicl r10,r10,48,1
rotldi r10,r10,16
mtmsrd r10,1
ld r9,TI_FLAGS(r12)
andi. r0,r9,(_TIF_SYSCALL_T_OR_A|_TIF_SIGPENDING|_TIF_NEED_RESCHED)
bne- syscall_exit_work
ld r7,_NIP(r1)
stdcx. r0,0,r1 /* to clear the reservation */
andi. r6,r8,MSR_PR
ld r4,_LINK(r1)
beq- 1f /* only restore r13 if */
ld r13,GPR13(r1) /* returning to usermode */
1: ld r2,GPR2(r1)
li r12,MSR_RI
andc r11,r10,r12
mtmsrd r11,1 /* clear MSR.RI */
ld r1,GPR1(r1)
mtlr r4
mtcr r5
mtspr SPRN_SRR0,r7
mtspr SPRN_SRR1,r8
rfid
b . /* prevent speculative execution */
syscall_enosys:
li r3,-ENOSYS
std r3,RESULT(r1)
clrrdi r12,r1,THREAD_SHIFT
ld r5,_CCR(r1)
syscall_error:
lbz r11,TI_SC_NOERR(r12)
cmpwi 0,r11,0
bne- syscall_error_cont
neg r3,r3
oris r5,r5,0x1000 /* Set SO bit in CR */
std r5,_CCR(r1)
b syscall_error_cont
/* Traced system call support */
syscall_dotrace:
bl .save_nvgprs
addi r3,r1,STACK_FRAME_OVERHEAD
bl .do_syscall_trace_enter
ld r0,GPR0(r1) /* Restore original registers */
ld r3,GPR3(r1)
ld r4,GPR4(r1)
ld r5,GPR5(r1)
ld r6,GPR6(r1)
ld r7,GPR7(r1)
ld r8,GPR8(r1)
addi r9,r1,STACK_FRAME_OVERHEAD
clrrdi r10,r1,THREAD_SHIFT
ld r10,TI_FLAGS(r10)
b syscall_dotrace_cont
syscall_exit_trace:
std r3,GPR3(r1)
bl .save_nvgprs
addi r3,r1,STACK_FRAME_OVERHEAD
bl .do_syscall_trace_leave
REST_NVGPRS(r1)
ld r3,GPR3(r1)
ld r5,_CCR(r1)
clrrdi r12,r1,THREAD_SHIFT
b syscall_exit_trace_cont
/* Stuff to do on exit from a system call. */
syscall_exit_work:
std r3,GPR3(r1)
std r5,_CCR(r1)
b .ret_from_except_lite
/* Save non-volatile GPRs, if not already saved. */
_GLOBAL(save_nvgprs)
ld r11,_TRAP(r1)
andi. r0,r11,1
beqlr-
SAVE_NVGPRS(r1)
clrrdi r0,r11,1
std r0,_TRAP(r1)
blr
/*
* The sigsuspend and rt_sigsuspend system calls can call do_signal
* and thus put the process into the stopped state where we might
* want to examine its user state with ptrace. Therefore we need
* to save all the nonvolatile registers (r14 - r31) before calling
* the C code. Similarly, fork, vfork and clone need the full
* register state on the stack so that it can be copied to the child.
*/
_GLOBAL(ppc32_sigsuspend)
bl .save_nvgprs
bl .compat_sys_sigsuspend
b 70f
_GLOBAL(ppc64_rt_sigsuspend)
bl .save_nvgprs
bl .sys_rt_sigsuspend
b 70f
_GLOBAL(ppc32_rt_sigsuspend)
bl .save_nvgprs
bl .compat_sys_rt_sigsuspend
70: cmpdi 0,r3,0
/* If it returned an error, we need to return via syscall_exit to set
the SO bit in cr0 and potentially stop for ptrace. */
bne syscall_exit
/* If sigsuspend() returns zero, we are going into a signal handler. We
may need to call audit_syscall_exit() to mark the exit from sigsuspend() */
#ifdef CONFIG_AUDITSYSCALL
ld r3,PACACURRENT(r13)
ld r4,AUDITCONTEXT(r3)
cmpdi 0,r4,0
beq .ret_from_except /* No audit_context: Leave immediately. */
li r4, 2 /* AUDITSC_FAILURE */
li r5,-4 /* It's always -EINTR */
bl .audit_syscall_exit
#endif
b .ret_from_except
_GLOBAL(ppc_fork)
bl .save_nvgprs
bl .sys_fork
b syscall_exit
_GLOBAL(ppc_vfork)
bl .save_nvgprs
bl .sys_vfork
b syscall_exit
_GLOBAL(ppc_clone)
bl .save_nvgprs
bl .sys_clone
b syscall_exit
_GLOBAL(ppc32_swapcontext)
bl .save_nvgprs
bl .compat_sys_swapcontext
b 80f
_GLOBAL(ppc64_swapcontext)
bl .save_nvgprs
bl .sys_swapcontext
b 80f
_GLOBAL(ppc32_sigreturn)
bl .compat_sys_sigreturn
b 80f
_GLOBAL(ppc32_rt_sigreturn)
bl .compat_sys_rt_sigreturn
b 80f
_GLOBAL(ppc64_rt_sigreturn)
bl .sys_rt_sigreturn
80: cmpdi 0,r3,0
blt syscall_exit
clrrdi r4,r1,THREAD_SHIFT
ld r4,TI_FLAGS(r4)
andi. r4,r4,(_TIF_SYSCALL_T_OR_A|_TIF_SINGLESTEP)
beq+ 81f
addi r3,r1,STACK_FRAME_OVERHEAD
bl .do_syscall_trace_leave
81: b .ret_from_except
_GLOBAL(ret_from_fork)
bl .schedule_tail
REST_NVGPRS(r1)
li r3,0
b syscall_exit
/*
* This routine switches between two different tasks. The process
* state of one is saved on its kernel stack. Then the state
* of the other is restored from its kernel stack. The memory
* management hardware is updated to the second process's state.
* Finally, we can return to the second process, via ret_from_except.
* On entry, r3 points to the THREAD for the current task, r4
* points to the THREAD for the new task.
*
* Note: there are two ways to get to the "going out" portion
* of this code; either by coming in via the entry (_switch)
* or via "fork" which must set up an environment equivalent
* to the "_switch" path. If you change this you'll have to change
* the fork code also.
*
* The code which creates the new task context is in 'copy_thread'
* in arch/ppc64/kernel/process.c
*/
.align 7
_GLOBAL(_switch)
mflr r0
std r0,16(r1)
stdu r1,-SWITCH_FRAME_SIZE(r1)
/* r3-r13 are caller saved -- Cort */
SAVE_8GPRS(14, r1)
SAVE_10GPRS(22, r1)
mflr r20 /* Return to switch caller */
mfmsr r22
li r0, MSR_FP
#ifdef CONFIG_ALTIVEC
BEGIN_FTR_SECTION
oris r0,r0,MSR_VEC@h /* Disable altivec */
mfspr r24,SPRN_VRSAVE /* save vrsave register value */
std r24,THREAD_VRSAVE(r3)
END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
#endif /* CONFIG_ALTIVEC */
and. r0,r0,r22
beq+ 1f
andc r22,r22,r0
mtmsrd r22
isync
1: std r20,_NIP(r1)
mfcr r23
std r23,_CCR(r1)
std r1,KSP(r3) /* Set old stack pointer */
#ifdef CONFIG_SMP
/* We need a sync somewhere here to make sure that if the
* previous task gets rescheduled on another CPU, it sees all
* stores it has performed on this one.
*/
sync
#endif /* CONFIG_SMP */
addi r6,r4,-THREAD /* Convert THREAD to 'current' */
std r6,PACACURRENT(r13) /* Set new 'current' */
ld r8,KSP(r4) /* new stack pointer */
BEGIN_FTR_SECTION
clrrdi r6,r8,28 /* get its ESID */
clrrdi r9,r1,28 /* get current sp ESID */
clrldi. r0,r6,2 /* is new ESID c00000000? */
cmpd cr1,r6,r9 /* or is new ESID the same as current ESID? */
cror eq,4*cr1+eq,eq
beq 2f /* if yes, don't slbie it */
/* Bolt in the new stack SLB entry */
ld r7,KSP_VSID(r4) /* Get new stack's VSID */
oris r0,r6,(SLB_ESID_V)@h
ori r0,r0,(SLB_NUM_BOLTED-1)@l
slbie r6
slbie r6 /* Workaround POWER5 < DD2.1 issue */
slbmte r7,r0
isync
2:
END_FTR_SECTION_IFSET(CPU_FTR_SLB)
clrrdi r7,r8,THREAD_SHIFT /* base of new stack */
/* Note: this uses SWITCH_FRAME_SIZE rather than INT_FRAME_SIZE
because we don't need to leave the 288-byte ABI gap at the
top of the kernel stack. */
addi r7,r7,THREAD_SIZE-SWITCH_FRAME_SIZE
mr r1,r8 /* start using new stack pointer */
std r7,PACAKSAVE(r13)
ld r6,_CCR(r1)
mtcrf 0xFF,r6
#ifdef CONFIG_ALTIVEC
BEGIN_FTR_SECTION
ld r0,THREAD_VRSAVE(r4)
mtspr SPRN_VRSAVE,r0 /* if G4, restore VRSAVE reg */
END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
#endif /* CONFIG_ALTIVEC */
/* r3-r13 are destroyed -- Cort */
REST_8GPRS(14, r1)
REST_10GPRS(22, r1)
/* convert old thread to its task_struct for return value */
addi r3,r3,-THREAD
ld r7,_NIP(r1) /* Return to _switch caller in new task */
mtlr r7
addi r1,r1,SWITCH_FRAME_SIZE
blr
.align 7
_GLOBAL(ret_from_except)
ld r11,_TRAP(r1)
andi. r0,r11,1
bne .ret_from_except_lite
REST_NVGPRS(r1)
_GLOBAL(ret_from_except_lite)
/*
* Disable interrupts so that current_thread_info()->flags
* can't change between when we test it and when we return
* from the interrupt.
*/
mfmsr r10 /* Get current interrupt state */
rldicl r9,r10,48,1 /* clear MSR_EE */
rotldi r9,r9,16
mtmsrd r9,1 /* Update machine state */
#ifdef CONFIG_PREEMPT
clrrdi r9,r1,THREAD_SHIFT /* current_thread_info() */
li r0,_TIF_NEED_RESCHED /* bits to check */
ld r3,_MSR(r1)
ld r4,TI_FLAGS(r9)
/* Move MSR_PR bit in r3 to _TIF_SIGPENDING position in r0 */
rlwimi r0,r3,32+TIF_SIGPENDING-MSR_PR_LG,_TIF_SIGPENDING
and. r0,r4,r0 /* check NEED_RESCHED and maybe SIGPENDING */
bne do_work
#else /* !CONFIG_PREEMPT */
ld r3,_MSR(r1) /* Returning to user mode? */
andi. r3,r3,MSR_PR
beq restore /* if not, just restore regs and return */
/* Check current_thread_info()->flags */
clrrdi r9,r1,THREAD_SHIFT
ld r4,TI_FLAGS(r9)
andi. r0,r4,_TIF_USER_WORK_MASK
bne do_work
#endif
restore:
#ifdef CONFIG_PPC_ISERIES
ld r5,SOFTE(r1)
cmpdi 0,r5,0
beq 4f
/* Check for pending interrupts (iSeries) */
ld r3,PACALPPACA+LPPACAANYINT(r13)
cmpdi r3,0
beq+ 4f /* skip do_IRQ if no interrupts */
li r3,0
stb r3,PACAPROCENABLED(r13) /* ensure we are soft-disabled */
ori r10,r10,MSR_EE
mtmsrd r10 /* hard-enable again */
addi r3,r1,STACK_FRAME_OVERHEAD
bl .do_IRQ
b .ret_from_except_lite /* loop back and handle more */
4: stb r5,PACAPROCENABLED(r13)
#endif
ld r3,_MSR(r1)
andi. r0,r3,MSR_RI
beq- unrecov_restore
andi. r0,r3,MSR_PR
/*
* r13 is our per cpu area, only restore it if we are returning to
* userspace
*/
beq 1f
REST_GPR(13, r1)
1:
ld r3,_CTR(r1)
ld r0,_LINK(r1)
mtctr r3
mtlr r0
ld r3,_XER(r1)
mtspr SPRN_XER,r3
REST_8GPRS(5, r1)
stdcx. r0,0,r1 /* to clear the reservation */
mfmsr r0
li r2, MSR_RI
andc r0,r0,r2
mtmsrd r0,1
ld r0,_MSR(r1)
mtspr SPRN_SRR1,r0
ld r2,_CCR(r1)
mtcrf 0xFF,r2
ld r2,_NIP(r1)
mtspr SPRN_SRR0,r2
ld r0,GPR0(r1)
ld r2,GPR2(r1)
ld r3,GPR3(r1)
ld r4,GPR4(r1)
ld r1,GPR1(r1)
rfid
b . /* prevent speculative execution */
/* Note: this must change if we start using the TIF_NOTIFY_RESUME bit */
do_work:
#ifdef CONFIG_PREEMPT
andi. r0,r3,MSR_PR /* Returning to user mode? */
bne user_work
/* Check that preempt_count() == 0 and interrupts are enabled */
lwz r8,TI_PREEMPT(r9)
cmpwi cr1,r8,0
#ifdef CONFIG_PPC_ISERIES
ld r0,SOFTE(r1)
cmpdi r0,0
#else
andi. r0,r3,MSR_EE
#endif
crandc eq,cr1*4+eq,eq
bne restore
/* here we are preempting the current task */
1:
#ifdef CONFIG_PPC_ISERIES
li r0,1
stb r0,PACAPROCENABLED(r13)
#endif
ori r10,r10,MSR_EE
mtmsrd r10,1 /* reenable interrupts */
bl .preempt_schedule
mfmsr r10
clrrdi r9,r1,THREAD_SHIFT
rldicl r10,r10,48,1 /* disable interrupts again */
rotldi r10,r10,16
mtmsrd r10,1
ld r4,TI_FLAGS(r9)
andi. r0,r4,_TIF_NEED_RESCHED
bne 1b
b restore
user_work:
#endif
/* Enable interrupts */
ori r10,r10,MSR_EE
mtmsrd r10,1
andi. r0,r4,_TIF_NEED_RESCHED
beq 1f
bl .schedule
b .ret_from_except_lite
1: bl .save_nvgprs
li r3,0
addi r4,r1,STACK_FRAME_OVERHEAD
bl .do_signal
b .ret_from_except
unrecov_restore:
addi r3,r1,STACK_FRAME_OVERHEAD
bl .unrecoverable_exception
b unrecov_restore
#ifdef CONFIG_PPC_RTAS
/*
* On CHRP, the Run-Time Abstraction Services (RTAS) have to be
* called with the MMU off.
*
* In addition, we need to be in 32b mode, at least for now.
*
* Note: r3 is an input parameter to rtas, so don't trash it...
*/
_GLOBAL(enter_rtas)
mflr r0
std r0,16(r1)
stdu r1,-RTAS_FRAME_SIZE(r1) /* Save SP and create stack space. */
/* Because RTAS is running in 32b mode, it clobbers the high order half
* of all registers that it saves. We therefore save those registers
* RTAS might touch to the stack. (r0, r3-r13 are caller saved)
*/
SAVE_GPR(2, r1) /* Save the TOC */
SAVE_GPR(13, r1) /* Save paca */
SAVE_8GPRS(14, r1) /* Save the non-volatiles */
SAVE_10GPRS(22, r1) /* ditto */
mfcr r4
std r4,_CCR(r1)
mfctr r5
std r5,_CTR(r1)
mfspr r6,SPRN_XER
std r6,_XER(r1)
mfdar r7
std r7,_DAR(r1)
mfdsisr r8
std r8,_DSISR(r1)
mfsrr0 r9
std r9,_SRR0(r1)
mfsrr1 r10
std r10,_SRR1(r1)
/* There is no way it is acceptable to get here with interrupts enabled,
* check it with the asm equivalent of WARN_ON
*/
mfmsr r6
andi. r0,r6,MSR_EE
1: tdnei r0,0
.section __bug_table,"a"
.llong 1b,__LINE__ + 0x1000000, 1f, 2f
.previous
.section .rodata,"a"
1: .asciz __FILE__
2: .asciz "enter_rtas"
.previous
/* Unfortunately, the stack pointer and the MSR are also clobbered,
* so they are saved in the PACA which allows us to restore
* our original state after RTAS returns.
*/
std r1,PACAR1(r13)
std r6,PACASAVEDMSR(r13)
/* Setup our real return addr */
SET_REG_TO_LABEL(r4,.rtas_return_loc)
SET_REG_TO_CONST(r9,KERNELBASE)
sub r4,r4,r9
mtlr r4
li r0,0
ori r0,r0,MSR_EE|MSR_SE|MSR_BE|MSR_RI
andc r0,r6,r0
li r9,1
rldicr r9,r9,MSR_SF_LG,(63-MSR_SF_LG)
ori r9,r9,MSR_IR|MSR_DR|MSR_FE0|MSR_FE1|MSR_FP
andc r6,r0,r9
ori r6,r6,MSR_RI
sync /* disable interrupts so SRR0/1 */
mtmsrd r0 /* don't get trashed */
SET_REG_TO_LABEL(r4,rtas)
ld r5,RTASENTRY(r4) /* get the rtas->entry value */
ld r4,RTASBASE(r4) /* get the rtas->base value */
mtspr SPRN_SRR0,r5
mtspr SPRN_SRR1,r6
rfid
b . /* prevent speculative execution */
_STATIC(rtas_return_loc)
/* relocation is off at this point */
mfspr r4,SPRN_SPRG3 /* Get PACA */
SET_REG_TO_CONST(r5, KERNELBASE)
sub r4,r4,r5 /* RELOC the PACA base pointer */
mfmsr r6
li r0,MSR_RI
andc r6,r6,r0
sync
mtmsrd r6
ld r1,PACAR1(r4) /* Restore our SP */
LOADADDR(r3,.rtas_restore_regs)
ld r4,PACASAVEDMSR(r4) /* Restore our MSR */
mtspr SPRN_SRR0,r3
mtspr SPRN_SRR1,r4
rfid
b . /* prevent speculative execution */
_STATIC(rtas_restore_regs)
/* relocation is on at this point */
REST_GPR(2, r1) /* Restore the TOC */
REST_GPR(13, r1) /* Restore paca */
REST_8GPRS(14, r1) /* Restore the non-volatiles */
REST_10GPRS(22, r1) /* ditto */
mfspr r13,SPRN_SPRG3
ld r4,_CCR(r1)
mtcr r4
ld r5,_CTR(r1)
mtctr r5
ld r6,_XER(r1)
mtspr SPRN_XER,r6
ld r7,_DAR(r1)
mtdar r7
ld r8,_DSISR(r1)
mtdsisr r8
ld r9,_SRR0(r1)
mtsrr0 r9
ld r10,_SRR1(r1)
mtsrr1 r10
addi r1,r1,RTAS_FRAME_SIZE /* Unstack our frame */
ld r0,16(r1) /* get return address */
mtlr r0
blr /* return to caller */
#endif /* CONFIG_PPC_RTAS */
#ifdef CONFIG_PPC_MULTIPLATFORM
_GLOBAL(enter_prom)
mflr r0
std r0,16(r1)
stdu r1,-PROM_FRAME_SIZE(r1) /* Save SP and create stack space */
/* Because PROM is running in 32b mode, it clobbers the high order half
* of all registers that it saves. We therefore save those registers
* PROM might touch to the stack. (r0, r3-r13 are caller saved)
*/
SAVE_8GPRS(2, r1)
SAVE_GPR(13, r1)
SAVE_8GPRS(14, r1)
SAVE_10GPRS(22, r1)
mfcr r4
std r4,_CCR(r1)
mfctr r5
std r5,_CTR(r1)
mfspr r6,SPRN_XER
std r6,_XER(r1)
mfdar r7
std r7,_DAR(r1)
mfdsisr r8
std r8,_DSISR(r1)
mfsrr0 r9
std r9,_SRR0(r1)
mfsrr1 r10
std r10,_SRR1(r1)
mfmsr r11
std r11,_MSR(r1)
/* Get the PROM entrypoint */
ld r0,GPR4(r1)
mtlr r0
/* Switch MSR to 32 bits mode
*/
mfmsr r11
li r12,1
rldicr r12,r12,MSR_SF_LG,(63-MSR_SF_LG)
andc r11,r11,r12
li r12,1
rldicr r12,r12,MSR_ISF_LG,(63-MSR_ISF_LG)
andc r11,r11,r12
mtmsrd r11
isync
/* Restore arguments & enter PROM here... */
ld r3,GPR3(r1)
blrl
/* Just make sure that r1 top 32 bits didn't get
* corrupt by OF
*/
rldicl r1,r1,0,32
/* Restore the MSR (back to 64 bits) */
ld r0,_MSR(r1)
mtmsrd r0
isync
/* Restore other registers */
REST_GPR(2, r1)
REST_GPR(13, r1)
REST_8GPRS(14, r1)
REST_10GPRS(22, r1)
ld r4,_CCR(r1)
mtcr r4
ld r5,_CTR(r1)
mtctr r5
ld r6,_XER(r1)
mtspr SPRN_XER,r6
ld r7,_DAR(r1)
mtdar r7
ld r8,_DSISR(r1)
mtdsisr r8
ld r9,_SRR0(r1)
mtsrr0 r9
ld r10,_SRR1(r1)
mtsrr1 r10
addi r1,r1,PROM_FRAME_SIZE
ld r0,16(r1)
mtlr r0
blr
#endif /* CONFIG_PPC_MULTIPLATFORM */
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