powerpc/powernv: Add explicit fast-reboot support

Add a way to manually invoke a fast-reboot rather than setting the NVRAM
flag. The idea is to allow userspace to invoke a fast-reboot using the
optional string argument to the reboot() system call, or using the xmon
zr command so we don't need to leave around a persistent changes on
a system to use the feature.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200217024833.30580-2-oohall@gmail.com

diff --git a/arch/powerpc/include/asm/opal-api.h b/arch/powerpc/include/asm/opal-api.h
index c1f25a7..1dffa3c 100644 (file)
--- a/arch/powerpc/include/asm/opal-api.h
+++ b/arch/powerpc/include/asm/opal-api.h
@@ -1067,6 +1067,7 @@ enum {
        OPAL_REBOOT_PLATFORM_ERROR      = 1,
        OPAL_REBOOT_FULL_IPL            = 2,
        OPAL_REBOOT_MPIPL               = 3,
+       OPAL_REBOOT_FAST                = 4,
 };
 
 /* Argument to OPAL_PCI_TCE_KILL */

diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platforms/powernv/setup.c
index a8fe630..3bc188d 100644 (file)
--- a/arch/powerpc/platforms/powernv/setup.c
+++ b/arch/powerpc/platforms/powernv/setup.c
@@ -237,6 +237,8 @@ static void  __noreturn pnv_restart(char *cmd)
                        rc = opal_cec_reboot2(OPAL_REBOOT_MPIPL, NULL);
                else if (strcmp(cmd, "error") == 0)
                        rc = opal_cec_reboot2(OPAL_REBOOT_PLATFORM_ERROR, NULL);
+               else if (strcmp(cmd, "fast") == 0)
+                       rc = opal_cec_reboot2(OPAL_REBOOT_FAST, NULL);
                else
                        rc = OPAL_UNSUPPORTED;