diff mbox series

[v4,08/12] ppc64/kexec_file: setup the stack for purgatory

Message ID 159524963052.20855.4032160058093572014.stgit@hbathini.in.ibm.com (mailing list archive)
State Superseded
Headers show
Series ppc64: enable kdump support for kexec_file_load syscall | expand

Commit Message

Hari Bathini July 20, 2020, 12:53 p.m. UTC 
To avoid any weird errors, the purgatory should run with its own
stack. Set one up by adding the stack buffer to .data section of
the purgatory. Also, setup opal base & entry values in r8 & r9
registers to help early OPAL debugging.

Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Tested-by: Pingfan Liu <piliu@redhat.com>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
---

v3 -> v4:
* Fixed stack_buf to be quadword aligned in accordance with ABI.
* Added missing of_node_put() in setup_purgatory_ppc64().
* Added Reviewed-by tag from Thiago.

v2 -> v3:
* Unchanged. Added Tested-by tag from Pingfan.

v1 -> v2:
* Setting up opal base & entry values in r8 & r9 for early OPAL debug.


 arch/powerpc/include/asm/kexec.h       |    4 ++++
 arch/powerpc/kexec/file_load_64.c      |   30 ++++++++++++++++++++++++++++++
 arch/powerpc/purgatory/trampoline_64.S |   32 ++++++++++++++++++++++++++++++++
 3 files changed, 66 insertions(+)
diff mbox series

Patch

diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
index 835dc92..00988da 100644
--- a/arch/powerpc/include/asm/kexec.h
+++ b/arch/powerpc/include/asm/kexec.h
@@ -45,6 +45,10 @@ 
 #define KEXEC_ARCH KEXEC_ARCH_PPC
 #endif
 
+#ifdef CONFIG_KEXEC_FILE
+#define KEXEC_PURGATORY_STACK_SIZE	16384	/* 16KB stack size */
+#endif
+
 #define KEXEC_STATE_NONE 0
 #define KEXEC_STATE_IRQS_OFF 1
 #define KEXEC_STATE_REAL_MODE 2
diff --git a/arch/powerpc/kexec/file_load_64.c b/arch/powerpc/kexec/file_load_64.c
index 20e638d..7f1f31c 100644
--- a/arch/powerpc/kexec/file_load_64.c
+++ b/arch/powerpc/kexec/file_load_64.c
@@ -946,6 +946,8 @@  int setup_purgatory_ppc64(struct kimage *image, const void *slave_code,
 			  const void *fdt, unsigned long kernel_load_addr,
 			  unsigned long fdt_load_addr)
 {
+	struct device_node *dn = NULL;
+	void *stack_buf;
 	uint64_t val;
 	int ret;
 
@@ -969,13 +971,41 @@  int setup_purgatory_ppc64(struct kimage *image, const void *slave_code,
 			goto out;
 	}
 
+	/* Setup the stack top */
+	stack_buf = kexec_purgatory_get_symbol_addr(image, "stack_buf");
+	if (!stack_buf)
+		goto out;
+
+	val = (u64)stack_buf + KEXEC_PURGATORY_STACK_SIZE;
+	ret = kexec_purgatory_get_set_symbol(image, "stack", &val, sizeof(val),
+					     false);
+	if (ret)
+		goto out;
+
 	/* Setup the TOC pointer */
 	val = get_toc_ptr(&(image->purgatory_info));
 	ret = kexec_purgatory_get_set_symbol(image, "my_toc", &val, sizeof(val),
 					     false);
+	if (ret)
+		goto out;
+
+	/* Setup OPAL base & entry values */
+	dn = of_find_node_by_path("/ibm,opal");
+	if (dn) {
+		of_property_read_u64(dn, "opal-base-address", &val);
+		ret = kexec_purgatory_get_set_symbol(image, "opal_base", &val,
+						     sizeof(val), false);
+		if (ret)
+			goto out;
+
+		of_property_read_u64(dn, "opal-entry-address", &val);
+		ret = kexec_purgatory_get_set_symbol(image, "opal_entry", &val,
+						     sizeof(val), false);
+	}
 out:
 	if (ret)
 		pr_err("Failed to setup purgatory symbols");
+	of_node_put(dn);
 	return ret;
 }
 
diff --git a/arch/powerpc/purgatory/trampoline_64.S b/arch/powerpc/purgatory/trampoline_64.S
index b375843..1615dfc 100644
--- a/arch/powerpc/purgatory/trampoline_64.S
+++ b/arch/powerpc/purgatory/trampoline_64.S
@@ -9,6 +9,7 @@ 
  * Copyright (C) 2013, Anton Blanchard, IBM Corporation
  */
 
+#include <asm/kexec.h>
 #include <asm/asm-compat.h>
 
 	.machine ppc64
@@ -53,6 +54,8 @@  master:
 
 	ld	%r2,(my_toc - 0b)(%r18)		/* setup toc */
 
+	ld	%r1,(stack - 0b)(%r18)		/* setup stack */
+
 	/* load device-tree address */
 	ld	%r3, (dt_offset - 0b)(%r18)
 	mr	%r16,%r3	/* save dt address in reg16 */
@@ -63,6 +66,10 @@  master:
 	li	%r4,28
 	STWX_BE	%r17,%r3,%r4	/* Store my cpu as __be32 at byte 28 */
 1:
+	/* Load opal base and entry values in r8 & r9 respectively */
+	ld	%r8,(opal_base - 0b)(%r18)
+	ld	%r9,(opal_entry - 0b)(%r18)
+
 	/* load the kernel address */
 	ld	%r4,(kernel - 0b)(%r18)
 
@@ -110,6 +117,24 @@  my_toc:
 	.8byte  0x0
 	.size my_toc, . - my_toc
 
+	.balign 8
+	.globl stack
+stack:
+	.8byte  0x0
+	.size stack, . - stack
+
+	.balign 8
+	.globl opal_base
+opal_base:
+	.8byte  0x0
+	.size opal_base, . - opal_base
+
+	.balign 8
+	.globl opal_entry
+opal_entry:
+	.8byte  0x0
+	.size opal_entry, . - opal_entry
+
 	.data
 	.balign 8
 .globl purgatory_sha256_digest
@@ -122,3 +147,10 @@  purgatory_sha256_digest:
 purgatory_sha_regions:
 	.skip	8 * 2 * 16
 	.size purgatory_sha_regions, . - purgatory_sha_regions
+
+	/* Stack must be quadword aligned */
+	.balign 16
+.globl stack_buf
+stack_buf:
+	.skip	KEXEC_PURGATORY_STACK_SIZE
+	.size stack_buf, . - stack_buf