powerpc/pseries/ras: Avoid calling rtas_token() in NMI paths

In the interest of reducing code and possible failures in the
machine check and system reset paths, grab the "ibm,nmi-interlock"
token at init time.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Link: https://lore.kernel.org/r/20200508043408.886394-6-npiggin@gmail.com

diff --git a/arch/powerpc/include/asm/firmware.h b/arch/powerpc/include/asm/firmware.h
index ca33f4ef6cb46ee8ce8477e13f12f3be074ac28a..6003c2e533a082d4d10a6c3ab10353b507f17720 100644 (file)
--- a/arch/powerpc/include/asm/firmware.h
+++ b/arch/powerpc/include/asm/firmware.h
@@ -128,6 +128,7 @@ extern void machine_check_fwnmi(void);
 
 /* This is true if we are using the firmware NMI handler (typically LPAR) */
 extern int fwnmi_active;
+extern int ibm_nmi_interlock_token;
 
 extern unsigned int __start___fw_ftr_fixup, __stop___fw_ftr_fixup;
 

diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c
index 1d1da639b8b7e41fa88440380e3ebc7577617596..ac92f8687ea3714c33809763235c2b744a68384a 100644 (file)
--- a/arch/powerpc/platforms/pseries/ras.c
+++ b/arch/powerpc/platforms/pseries/ras.c
@@ -458,7 +458,7 @@ static struct rtas_error_log *fwnmi_get_errinfo(struct pt_regs *regs)
  */
 static void fwnmi_release_errinfo(void)
 {
-       int ret = rtas_call(rtas_token("ibm,nmi-interlock"), 0, 1, NULL);
+       int ret = rtas_call(ibm_nmi_interlock_token, 0, 1, NULL);
        if (ret != 0)
                printk(KERN_ERR "FWNMI: nmi-interlock failed: %d\n", ret);
 }

diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index 1b55e804927d367cd04fc0c026ce71ba66094c91..64d18f4bf09392784f86b99c6ea4c92c112bc67e 100644 (file)
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -84,6 +84,7 @@ unsigned long CMO_PageSize = (ASM_CONST(1) << IOMMU_PAGE_SHIFT_4K);
 EXPORT_SYMBOL(CMO_PageSize);
 
 int fwnmi_active;  /* TRUE if an FWNMI handler is present */
+int ibm_nmi_interlock_token;
 
 static void pSeries_show_cpuinfo(struct seq_file *m)
 {
@@ -114,9 +115,14 @@ static void __init fwnmi_init(void)
        struct slb_entry *slb_ptr;
        size_t size;
 #endif
+       int ibm_nmi_register_token;
 
-       int ibm_nmi_register = rtas_token("ibm,nmi-register");
-       if (ibm_nmi_register == RTAS_UNKNOWN_SERVICE)
+       ibm_nmi_register_token = rtas_token("ibm,nmi-register");
+       if (ibm_nmi_register_token == RTAS_UNKNOWN_SERVICE)
+               return;
+
+       ibm_nmi_interlock_token = rtas_token("ibm,nmi-interlock");
+       if (WARN_ON(ibm_nmi_interlock_token == RTAS_UNKNOWN_SERVICE))
                return;
 
        /* If the kernel's not linked at zero we point the firmware at low
@@ -124,8 +130,8 @@ static void __init fwnmi_init(void)
        system_reset_addr  = __pa(system_reset_fwnmi) - PHYSICAL_START;
        machine_check_addr = __pa(machine_check_fwnmi) - PHYSICAL_START;
 
-       if (0 == rtas_call(ibm_nmi_register, 2, 1, NULL, system_reset_addr,
-                               machine_check_addr))
+       if (0 == rtas_call(ibm_nmi_register_token, 2, 1, NULL,
+                          system_reset_addr, machine_check_addr))
                fwnmi_active = 1;
 
        /*