From e844b1eeae42dc93bf13e67812a95ee7b58be8c7 Mon Sep 17 00:00:00 2001 From: Anton Blanchard Date: Wed, 20 Nov 2013 22:14:59 +1100 Subject: [PATCH] pseries: Add H_SET_MODE to change exception endianness On little endian builds call H_SET_MODE so exceptions have the correct endianness. We need to reset the endian during kexec so do that in the MMU hashtable clear callback. Signed-off-by: Anton Blanchard Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/include/asm/hvcall.h | 2 ++ arch/powerpc/include/asm/plpar_wrappers.h | 26 ++++++++++++++ arch/powerpc/platforms/pseries/lpar.c | 17 +++++++++ arch/powerpc/platforms/pseries/setup.c | 42 +++++++++++++++++++++++ 4 files changed, 87 insertions(+) diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h index 0c7f2bfcf134..d8b600b3f058 100644 --- a/arch/powerpc/include/asm/hvcall.h +++ b/arch/powerpc/include/asm/hvcall.h @@ -403,6 +403,8 @@ static inline unsigned long cmo_get_page_size(void) extern long pSeries_enable_reloc_on_exc(void); extern long pSeries_disable_reloc_on_exc(void); +extern long pseries_big_endian_exceptions(void); + #else #define pSeries_enable_reloc_on_exc() do {} while (0) diff --git a/arch/powerpc/include/asm/plpar_wrappers.h b/arch/powerpc/include/asm/plpar_wrappers.h index a63b045e707c..12c32c5f533d 100644 --- a/arch/powerpc/include/asm/plpar_wrappers.h +++ b/arch/powerpc/include/asm/plpar_wrappers.h @@ -287,6 +287,32 @@ static inline long disable_reloc_on_exceptions(void) { return plpar_set_mode(0, 3, 0, 0); } +/* + * Take exceptions in big endian mode on this partition + * + * Note: this call has a partition wide scope and can take a while to complete. + * If it returns H_LONG_BUSY_* it should be retried periodically until it + * returns H_SUCCESS. + */ +static inline long enable_big_endian_exceptions(void) +{ + /* mflags = 0: big endian exceptions */ + return plpar_set_mode(0, 4, 0, 0); +} + +/* + * Take exceptions in little endian mode on this partition + * + * Note: this call has a partition wide scope and can take a while to complete. + * If it returns H_LONG_BUSY_* it should be retried periodically until it + * returns H_SUCCESS. + */ +static inline long enable_little_endian_exceptions(void) +{ + /* mflags = 1: little endian exceptions */ + return plpar_set_mode(1, 4, 0, 0); +} + static inline long plapr_set_ciabr(unsigned long ciabr) { return plpar_set_mode(0, 1, ciabr, 0); diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c index 356bc75ca74f..4fca3def9db9 100644 --- a/arch/powerpc/platforms/pseries/lpar.c +++ b/arch/powerpc/platforms/pseries/lpar.c @@ -245,6 +245,23 @@ static void pSeries_lpar_hptab_clear(void) &(ptes[j].pteh), &(ptes[j].ptel)); } } + +#ifdef __LITTLE_ENDIAN__ + /* Reset exceptions to big endian */ + if (firmware_has_feature(FW_FEATURE_SET_MODE)) { + long rc; + + rc = pseries_big_endian_exceptions(); + /* + * At this point it is unlikely panic() will get anything + * out to the user, but at least this will stop us from + * continuing on further and creating an even more + * difficult to debug situation. + */ + if (rc) + panic("Could not enable big endian exceptions"); + } +#endif } /* diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c index 1f97e2b87a62..c1f190858701 100644 --- a/arch/powerpc/platforms/pseries/setup.c +++ b/arch/powerpc/platforms/pseries/setup.c @@ -442,6 +442,32 @@ static void pSeries_machine_kexec(struct kimage *image) } #endif +#ifdef __LITTLE_ENDIAN__ +long pseries_big_endian_exceptions(void) +{ + long rc; + + while (1) { + rc = enable_big_endian_exceptions(); + if (!H_IS_LONG_BUSY(rc)) + return rc; + mdelay(get_longbusy_msecs(rc)); + } +} + +static long pseries_little_endian_exceptions(void) +{ + long rc; + + while (1) { + rc = enable_little_endian_exceptions(); + if (!H_IS_LONG_BUSY(rc)) + return rc; + mdelay(get_longbusy_msecs(rc)); + } +} +#endif + static void __init pSeries_setup_arch(void) { panic_timeout = 10; @@ -698,6 +724,22 @@ static int __init pSeries_probe(void) /* Now try to figure out if we are running on LPAR */ of_scan_flat_dt(pseries_probe_fw_features, NULL); +#ifdef __LITTLE_ENDIAN__ + if (firmware_has_feature(FW_FEATURE_SET_MODE)) { + long rc; + /* + * Tell the hypervisor that we want our exceptions to + * be taken in little endian mode. If this fails we don't + * want to use BUG() because it will trigger an exception. + */ + rc = pseries_little_endian_exceptions(); + if (rc) { + ppc_md.progress("H_SET_MODE LE exception fail", 0); + panic("Could not enable little endian exceptions"); + } + } +#endif + if (firmware_has_feature(FW_FEATURE_LPAR)) hpte_init_lpar(); else -- 2.20.1