[PATCH 2/2] powerpc/powernv: Wire up OPAL address lookups

[Nicholas Piggin <npiggin@gmail.com>]

Use ARCH_HAS_ADDRESS_LOOKUP to look up the opal symbol table. This
allows crashes and xmon debugging to print firmware symbols.

  Oops: System Reset, sig: 6 [#1]
  LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA PowerNV
  Modules linked in:
  CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.6.0-rc2-dirty #903
  NIP:  0000000030020434 LR: 000000003000378c CTR: 0000000030020414
  REGS: c0000000fffc3d70 TRAP: 0100   Not tainted  (5.6.0-rc2-dirty)
  MSR:  9000000002101002 <SF,HV,VEC,ME,RI>  CR: 28022284  XER: 20040000
  CFAR: 0000000030003788 IRQMASK: 3
  GPR00: 000000003000378c 0000000031c13c90 0000000030136200 c0000000012cfa10
  GPR04: c0000000012cfa10 0000000000000010 0000000000000000 0000000031c10060
  GPR08: c0000000012cfaaf 0000000030003640 0000000000000000 0000000000000001
  GPR12: 00000000300e0000 c000000001490000 0000000000000000 c00000000139c588
  GPR16: 0000000031c10000 c00000000125a900 0000000000000000 c0000000012076a8
  GPR20: c0000000012a3950 0000000000000001 0000000031c10060 c0000000012cfaaf
  GPR24: 0000000000000019 0000000030003640 0000000000000000 0000000000000000
  GPR28: 0000000000000010 c0000000012cfa10 0000000000000000 0000000000000000
  NIP [0000000030020434] .dummy_console_write_buffer_space+0x20/0x64 [OPAL]
  LR [000000003000378c] opal_entry+0x14c/0x17c [OPAL]

This won't unwind the firmware stack (or its Linux caller) properly if
firmware and kernel endians don't match, but that problem could be solved
in powerpc's unwinder.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/powerpc/Kconfig                       |  1 +
 arch/powerpc/include/asm/opal-api.h        |  6 +++-
 arch/powerpc/include/asm/opal.h            |  3 ++
 arch/powerpc/platforms/powernv/opal-call.c |  2 ++
 arch/powerpc/platforms/powernv/opal.c      | 40 ++++++++++++++++++++++
 5 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 497b7d0b2d7e..4d32b02d35e8 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -115,6 +115,7 @@ config PPC
 	# Please keep this list sorted alphabetically.
 	#
 	select ARCH_32BIT_OFF_T if PPC32
+	select ARCH_HAS_ADDRESS_LOOKUP		if PPC_POWERNV
 	select ARCH_HAS_DEBUG_VIRTUAL
 	select ARCH_HAS_DEVMEM_IS_ALLOWED
 	select ARCH_HAS_ELF_RANDOMIZE
diff --git a/arch/powerpc/include/asm/opal-api.h b/arch/powerpc/include/asm/opal-api.h
index c1f25a760eb1..c3a2a797177a 100644
--- a/arch/powerpc/include/asm/opal-api.h
+++ b/arch/powerpc/include/asm/opal-api.h
@@ -214,7 +214,11 @@
 #define OPAL_SECVAR_GET				176
 #define OPAL_SECVAR_GET_NEXT			177
 #define OPAL_SECVAR_ENQUEUE_UPDATE		178
-#define OPAL_LAST				178
+#define OPAL_PHB_SET_OPTION			179
+#define OPAL_PHB_GET_OPTION			180
+#define OPAL_GET_SYMBOL				181
+#define OPAL_LOOKUP_SYMBOL			182
+#define OPAL_LAST				182
 
 #define QUIESCE_HOLD			1 /* Spin all calls at entry */
 #define QUIESCE_REJECT			2 /* Fail all calls with OPAL_BUSY */
diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index 9986ac34b8e2..ef2d9273f06f 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -312,6 +312,9 @@ s64 opal_mpipl_query_tag(enum opal_mpipl_tags tag, u64 *addr);
 s64 opal_signal_system_reset(s32 cpu);
 s64 opal_quiesce(u64 shutdown_type, s32 cpu);
 
+int64_t opal_get_symbol(uint64_t addr, __be64 *symaddr, __be64 *symsize, char *namebuf, uint64_t buflen);
+int64_t opal_lookup_symbol(const char *name, __be64 *symaddr, __be64 *symsize);
+
 /* Internal functions */
 extern int early_init_dt_scan_opal(unsigned long node, const char *uname,
 				   int depth, void *data);
diff --git a/arch/powerpc/platforms/powernv/opal-call.c b/arch/powerpc/platforms/powernv/opal-call.c
index 5cd0f52d258f..ba11112d94df 100644
--- a/arch/powerpc/platforms/powernv/opal-call.c
+++ b/arch/powerpc/platforms/powernv/opal-call.c
@@ -293,3 +293,5 @@ OPAL_CALL(opal_mpipl_query_tag,			OPAL_MPIPL_QUERY_TAG);
 OPAL_CALL(opal_secvar_get,			OPAL_SECVAR_GET);
 OPAL_CALL(opal_secvar_get_next,			OPAL_SECVAR_GET_NEXT);
 OPAL_CALL(opal_secvar_enqueue_update,		OPAL_SECVAR_ENQUEUE_UPDATE);
+OPAL_CALL(opal_get_symbol,			OPAL_GET_SYMBOL);
+OPAL_CALL(opal_lookup_symbol,			OPAL_LOOKUP_SYMBOL);
diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index 2b3dfd0b6cdd..fdf6c4e6f7f9 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -107,6 +107,46 @@ void opal_configure_cores(void)
 		cur_cpu_spec->cpu_restore();
 }
 
+const char *arch_address_lookup(unsigned long addr,
+			    unsigned long *symbolsize,
+			    unsigned long *offset,
+			    char **modname, char *namebuf)
+{
+	__be64 symaddr;
+	__be64 symsize;
+
+	if (!firmware_has_feature(FW_FEATURE_OPAL))
+		return NULL;
+
+	if (opal_get_symbol(addr, &symaddr, &symsize, namebuf,
+			cpu_to_be64(KSYM_NAME_LEN)) != OPAL_SUCCESS)
+		return NULL;
+
+	*symbolsize = be64_to_cpu(symsize);
+	*offset = addr - be64_to_cpu(symaddr);
+	*modname = "OPAL";
+
+	return namebuf;
+}
+
+unsigned long arch_address_lookup_name(const char *name)
+{
+	__be64 addr;
+	__be64 size;
+
+	if (!firmware_has_feature(FW_FEATURE_OPAL))
+		return 0;
+
+	/* opal: prefix allows lookup of symbols that clash with kernel */
+	if (!strncasecmp(name, "opal:", strlen("opal:")))
+		name += strlen("opal:");
+
+	if (opal_lookup_symbol(name, &addr, &size) != OPAL_SUCCESS)
+		return 0;
+
+	return be64_to_cpu(addr);
+}
+
 int __init early_init_dt_scan_opal(unsigned long node,
 				   const char *uname, int depth, void *data)
 {
-- 
2.23.0