[PATCH] powerpc: Ignore DSI error caused by the copy/paste instruction
Haren Myneni
haren at linux.ibm.com
Thu Sep 22 18:29:47 AEST 2022
DSI error will be generated when the paste operation is issued on
the suspended NX window due to NX state changes. The hypervisor
expects the partition to ignore this error during page pault
handling. To differentiate DSI caused by an actual HW configuration
or by the NX window, a new “ibm,pi-features” type value is defined.
Byte 0, bit 3 of pi-attribute-specifier-type is now defined to
indicate this DSI error.
This patch adds changes to read ibm,pi-features property and ignore
DSI error in the page fault handling if CPU_FTR_NX_DSI if defined.
Signed-off-by: Haren Myneni <haren at linux.ibm.com>
---
arch/powerpc/include/asm/cputable.h | 5 ++--
arch/powerpc/kernel/prom.c | 36 +++++++++++++++++++++--------
arch/powerpc/mm/fault.c | 17 +++++++++++++-
3 files changed, 45 insertions(+), 13 deletions(-)
diff --git a/arch/powerpc/include/asm/cputable.h b/arch/powerpc/include/asm/cputable.h
index ae8c3e13cfce..8dc9949b6365 100644
--- a/arch/powerpc/include/asm/cputable.h
+++ b/arch/powerpc/include/asm/cputable.h
@@ -192,6 +192,7 @@ static inline void cpu_feature_keys_init(void) { }
#define CPU_FTR_P9_RADIX_PREFETCH_BUG LONG_ASM_CONST(0x0002000000000000)
#define CPU_FTR_ARCH_31 LONG_ASM_CONST(0x0004000000000000)
#define CPU_FTR_DAWR1 LONG_ASM_CONST(0x0008000000000000)
+#define CPU_FTR_NX_DSI LONG_ASM_CONST(0x0010000000000000)
#ifndef __ASSEMBLY__
@@ -429,7 +430,7 @@ static inline void cpu_feature_keys_init(void) { }
CPU_FTR_CFAR | CPU_FTR_HVMODE | CPU_FTR_VMX_COPY | \
CPU_FTR_DBELL | CPU_FTR_HAS_PPR | CPU_FTR_ARCH_207S | \
CPU_FTR_TM_COMP | CPU_FTR_ARCH_300 | CPU_FTR_P9_TLBIE_STQ_BUG | \
- CPU_FTR_P9_TLBIE_ERAT_BUG | CPU_FTR_P9_TIDR)
+ CPU_FTR_P9_TLBIE_ERAT_BUG | CPU_FTR_P9_TIDR | CPU_FTR_NX_DSI)
#define CPU_FTRS_POWER9_DD2_0 (CPU_FTRS_POWER9 | CPU_FTR_P9_RADIX_PREFETCH_BUG)
#define CPU_FTRS_POWER9_DD2_1 (CPU_FTRS_POWER9 | \
CPU_FTR_P9_RADIX_PREFETCH_BUG | \
@@ -451,7 +452,7 @@ static inline void cpu_feature_keys_init(void) { }
CPU_FTR_CFAR | CPU_FTR_HVMODE | CPU_FTR_VMX_COPY | \
CPU_FTR_DBELL | CPU_FTR_HAS_PPR | CPU_FTR_ARCH_207S | \
CPU_FTR_ARCH_300 | CPU_FTR_ARCH_31 | \
- CPU_FTR_DAWR | CPU_FTR_DAWR1)
+ CPU_FTR_DAWR | CPU_FTR_DAWR1 | CPU_FTR_NX_DSI)
#define CPU_FTRS_CELL (CPU_FTR_LWSYNC | \
CPU_FTR_PPCAS_ARCH_V2 | CPU_FTR_CTRL | \
CPU_FTR_ALTIVEC_COMP | CPU_FTR_MMCRA | CPU_FTR_SMT | \
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index a730b951b64b..19047c582e9f 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -137,7 +137,7 @@ static void __init move_device_tree(void)
}
/*
- * ibm,pa-features is a per-cpu property that contains a string of
+ * ibm,pa/pi-features is a per-cpu property that contains a string of
* attribute descriptors, each of which has a 2 byte header plus up
* to 254 bytes worth of processor attribute bits. First header
* byte specifies the number of bytes following the header.
@@ -149,15 +149,17 @@ static void __init move_device_tree(void)
* is supported/not supported. Note that the bit numbers are
* big-endian to match the definition in PAPR.
*/
-static struct ibm_pa_feature {
+struct ibm_feature {
unsigned long cpu_features; /* CPU_FTR_xxx bit */
unsigned long mmu_features; /* MMU_FTR_xxx bit */
unsigned int cpu_user_ftrs; /* PPC_FEATURE_xxx bit */
unsigned int cpu_user_ftrs2; /* PPC_FEATURE2_xxx bit */
- unsigned char pabyte; /* byte number in ibm,pa-features */
+ unsigned char pabyte; /* byte number in ibm,pa/pi-features */
unsigned char pabit; /* bit number (big-endian) */
unsigned char invert; /* if 1, pa bit set => clear feature */
-} ibm_pa_features[] __initdata = {
+};
+
+static struct ibm_feature ibm_pa_features[] __initdata = {
{ .pabyte = 0, .pabit = 0, .cpu_user_ftrs = PPC_FEATURE_HAS_MMU },
{ .pabyte = 0, .pabit = 1, .cpu_user_ftrs = PPC_FEATURE_HAS_FPU },
{ .pabyte = 0, .pabit = 3, .cpu_features = CPU_FTR_CTRL },
@@ -179,9 +181,19 @@ static struct ibm_pa_feature {
{ .pabyte = 64, .pabit = 0, .cpu_features = CPU_FTR_DAWR1 },
};
+/*
+ * ibm,pi-features property provides the support of processor specific
+ * options not described in ibm,pa-features. Right now use byte 0, bit 3
+ * which indicates the occurrence of DSI interrupt when the paste operation
+ * on the suspended NX window.
+ */
+static struct ibm_feature ibm_pi_features[] __initdata = {
+ { .pabyte = 0, .pabit = 3, .cpu_features = CPU_FTR_NX_DSI },
+};
+
static void __init scan_features(unsigned long node, const unsigned char *ftrs,
unsigned long tablelen,
- struct ibm_pa_feature *fp,
+ struct ibm_feature *fp,
unsigned long ft_size)
{
unsigned long i, len, bit;
@@ -218,17 +230,18 @@ static void __init scan_features(unsigned long node, const unsigned char *ftrs,
}
}
-static void __init check_cpu_pa_features(unsigned long node)
+static void __init check_cpu_features(unsigned long node, char *name,
+ struct ibm_feature *fp,
+ unsigned long size)
{
const unsigned char *pa_ftrs;
int tablelen;
- pa_ftrs = of_get_flat_dt_prop(node, "ibm,pa-features", &tablelen);
+ pa_ftrs = of_get_flat_dt_prop(node, name, &tablelen);
if (pa_ftrs == NULL)
return;
- scan_features(node, pa_ftrs, tablelen,
- ibm_pa_features, ARRAY_SIZE(ibm_pa_features));
+ scan_features(node, pa_ftrs, tablelen, fp, size);
}
#ifdef CONFIG_PPC_64S_HASH_MMU
@@ -380,7 +393,10 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
identify_cpu(0, be32_to_cpup(prop));
check_cpu_feature_properties(node);
- check_cpu_pa_features(node);
+ check_cpu_features(node, "ibm,pa-features", ibm_pa_features,
+ ARRAY_SIZE(ibm_pa_features));
+ check_cpu_features(node, "ibm,pi-features", ibm_pi_features,
+ ARRAY_SIZE(ibm_pi_features));
}
identical_pvr_fixup(node);
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 014005428687..154cc1e85770 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -367,7 +367,22 @@ static void sanity_check_fault(bool is_write, bool is_user,
#elif defined(CONFIG_PPC_8xx)
#define page_fault_is_bad(__err) ((__err) & DSISR_NOEXEC_OR_G)
#elif defined(CONFIG_PPC64)
-#define page_fault_is_bad(__err) ((__err) & DSISR_BAD_FAULT_64S)
+static inline int page_fault_is_bad(unsigned long __err)
+{
+ unsigned long flag = DSISR_BAD_FAULT_64S;
+
+ /*
+ * PAPR 14.15.3.4.1
+ * If byte 0, bit 3 of pi-attribute-specifier-type in
+ * ibm,pi-features property is defined, ignore the DSI error
+ * which is caused by the paste instruction on the
+ * suspended NX window.
+ */
+ if (cpu_has_feature(CPU_FTR_NX_DSI))
+ flag &= ~DSISR_BAD_COPYPASTE;
+
+ return ((__err) & flag);
+}
#else
#define page_fault_is_bad(__err) ((__err) & DSISR_BAD_FAULT_32S)
#endif
--
2.26.3
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