Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 176 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/rtas_entry.S b/arch/powerpc/kernel/rtas_entry.S
new file mode 100644
index 000000000..6ce95ddad
--- /dev/null
+++ b/arch/powerpc/kernel/rtas_entry.S
@@ -0,0 +1,176 @@
+/* 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.
+	 * If we're in HV mode, RTAS must also run in HV mode, so extract MSR_HV
+	 * from the saved MSR value and insert into the value RTAS will use.
+	 */
+	extrdi	r0, r6, 1, 63 - MSR_HV_LG
+	LOAD_REG_IMMEDIATE(r6, MSR_ME | MSR_RI)
+	insrdi	r6, r0, 1, 63 - MSR_HV_LG
+
+	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 */