[PATCH] MIPS: extend hardware table walking support to MIPS64

[Paul Burton]

Extend the existing support for Hardware Table Walking (HTW) to MIPS64
systems by supporting PMDs & setting the pointer size bit in PWSize,
then ceasing to blacklist HTW on MIPS64 systems.

Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx>
---

 arch/mips/kernel/cpu-probe.c | 3 +--
 arch/mips/mm/tlbex.c         | 8 +++++++-
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index 571a8e6..417fa3d 100644
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -534,8 +534,7 @@ static inline unsigned int decode_config3(struct cpuinfo_mips *c)
 		c->options |= MIPS_CPU_SEGMENTS;
 	if (config3 & MIPS_CONF3_MSA)
 		c->ases |= MIPS_ASE_MSA;
-	/* Only tested on 32-bit cores */
-	if ((config3 & MIPS_CONF3_PW) && config_enabled(CONFIG_32BIT)) {
+	if (config3 & MIPS_CONF3_PW) {
 		c->htw_seq = 0;
 		c->options |= MIPS_CPU_HTW;
 	}
diff --git a/arch/mips/mm/tlbex.c b/arch/mips/mm/tlbex.c
index 323d1d3..6d22a33 100644
--- a/arch/mips/mm/tlbex.c
+++ b/arch/mips/mm/tlbex.c
@@ -2299,6 +2299,10 @@ static void config_htw_params(void)
 	/* re-initialize the PTI field including the even/odd bit */
 	pwfield &= ~MIPS_PWFIELD_PTI_MASK;
 	pwfield |= PAGE_SHIFT << MIPS_PWFIELD_PTI_SHIFT;
+	if (CONFIG_PGTABLE_LEVELS >= 3) {
+		pwfield &= ~MIPS_PWFIELD_MDI_MASK;
+		pwfield |= PMD_SHIFT << MIPS_PWFIELD_MDI_SHIFT;
+	}
 	/* Set the PTEI right shift */
 	ptei = _PAGE_GLOBAL_SHIFT << MIPS_PWFIELD_PTEI_SHIFT;
 	pwfield |= ptei;
@@ -2320,9 +2324,11 @@ static void config_htw_params(void)
 
 	pwsize = ilog2(PTRS_PER_PGD) << MIPS_PWSIZE_GDW_SHIFT;
 	pwsize |= ilog2(PTRS_PER_PTE) << MIPS_PWSIZE_PTW_SHIFT;
+	if (CONFIG_PGTABLE_LEVELS >= 3)
+		pwsize |= ilog2(PTRS_PER_PMD) << MIPS_PWSIZE_MDW_SHIFT;
 
 	/* If XPA has been enabled, PTEs are 64-bit in size. */
-	if (read_c0_pagegrain() & PG_ELPA)
+	if (config_enabled(CONFIG_64BITS) || (read_c0_pagegrain() & PG_ELPA))
 		pwsize |= 1;
 
 	write_c0_pwsize(pwsize);
-- 
2.5.3

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