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/* SPDX-License-Identifier: GPL-2.0-or-later */
#include <asm/asm-offsets.h>
#include <asm/bug.h>
#include <asm/page.h>
#include <asm/ppc_asm.h>
/*
* RTAS is called with MSR IR, DR, EE disabled, and LR in the return address.
*
* Note: r3 is an input parameter to rtas, so don't trash it...
*/
#ifdef CONFIG_PPC32
_GLOBAL(enter_rtas)
stwu r1,-INT_FRAME_SIZE(r1)
mflr r0
stw r0,INT_FRAME_SIZE+4(r1)
LOAD_REG_ADDR(r4, rtas)
lis r6,1f@ha /* physical return address for rtas */
addi r6,r6,1f@l
tophys(r6,r6)
lwz r8,RTASENTRY(r4)
lwz r4,RTASBASE(r4)
mfmsr r9
stw r9,8(r1)
li r9,MSR_KERNEL & ~(MSR_IR|MSR_DR)
mtlr r6
stw r1, THREAD + RTAS_SP(r2)
mtspr SPRN_SRR0,r8
mtspr SPRN_SRR1,r9
rfi
1:
lis r8, 1f@h
ori r8, r8, 1f@l
LOAD_REG_IMMEDIATE(r9,MSR_KERNEL)
mtspr SPRN_SRR0,r8
mtspr SPRN_SRR1,r9
rfi /* Reactivate MMU translation */
1:
lwz r8,INT_FRAME_SIZE+4(r1) /* get return address */
lwz r9,8(r1) /* original msr value */
addi r1,r1,INT_FRAME_SIZE
li r0,0
stw r0, THREAD + RTAS_SP(r2)
mtlr r8
mtmsr r9
blr /* return to caller */
_ASM_NOKPROBE_SYMBOL(enter_rtas)
#else /* CONFIG_PPC32 */
#include <asm/exception-64s.h>
/*
* 32-bit rtas on 64-bit machines has the additional problem that RTAS may
* not preserve the upper parts of registers it uses.
*/
_GLOBAL(enter_rtas)
mflr r0
std r0,16(r1)
stdu r1,-SWITCH_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-r12 are caller saved)
*/
SAVE_GPR(2, r1) /* Save the TOC */
SAVE_NVGPRS(r1) /* Save the non-volatiles */
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)
/* Temporary workaround to clear CR until RTAS can be modified to
* ignore all bits.
*/
li r0,0
mtcr r0
mfmsr r6
/* 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 */
LOAD_REG_ADDR(r4,rtas_return_loc)
clrldi r4,r4,2 /* convert to realmode address */
mtlr r4
__enter_rtas:
LOAD_REG_ADDR(r4, rtas)
ld r5,RTASENTRY(r4) /* get the rtas->entry value */
ld r4,RTASBASE(r4) /* get the rtas->base value */
/*
* RTAS runs in 32-bit big endian real mode, but leave MSR[RI] on as we
* may hit NMI (SRESET or MCE) while in RTAS. RTAS should disable RI in
* its critical regions (as specified in PAPR+ section 7.2.1). MSR[S]
* is not impacted by RFI_TO_KERNEL (only urfid can unset it). So if
* MSR[S] is set, it will remain when entering RTAS.
*/
LOAD_REG_IMMEDIATE(r6, MSR_ME | MSR_RI)
li r0,0
mtmsrd r0,1 /* disable RI before using SRR0/1 */
mtspr SPRN_SRR0,r5
mtspr SPRN_SRR1,r6
RFI_TO_KERNEL
b . /* prevent speculative execution */
rtas_return_loc:
FIXUP_ENDIAN
/* Set SF before anything. */
LOAD_REG_IMMEDIATE(r6, MSR_KERNEL & ~(MSR_IR|MSR_DR))
mtmsrd r6
/* relocation is off at this point */
GET_PACA(r13)
bcl 20,31,$+4
0: mflr r3
ld r3,(1f-0b)(r3) /* get &rtas_restore_regs */
ld r1,PACAR1(r13) /* Restore our SP */
ld r4,PACASAVEDMSR(r13) /* Restore our MSR */
mtspr SPRN_SRR0,r3
mtspr SPRN_SRR1,r4
RFI_TO_KERNEL
b . /* prevent speculative execution */
_ASM_NOKPROBE_SYMBOL(enter_rtas)
_ASM_NOKPROBE_SYMBOL(__enter_rtas)
_ASM_NOKPROBE_SYMBOL(rtas_return_loc)
.align 3
1: .8byte rtas_restore_regs
rtas_restore_regs:
/* relocation is on at this point */
REST_GPR(2, r1) /* Restore the TOC */
REST_NVGPRS(r1) /* Restore the non-volatiles */
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
addi r1,r1,SWITCH_FRAME_SIZE /* Unstack our frame */
ld r0,16(r1) /* get return address */
mtlr r0
blr /* return to caller */
#endif /* CONFIG_PPC32 */
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