[RFC PATCH v3 11/16] powerpc/e500: Switch to 64 bits PGD on 85xx (32 bits)

From: Christophe Leroy
Date: Sun May 26 2024 - 05:25:21 EST


At the time being when CONFIG_PTE_64BIT is selected, PTE entries are
64 bits but PGD entries are still 32 bits.

In order to allow leaf PMD entries, switch the PGD to 64 bits entries.

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
arch/powerpc/include/asm/pgtable-types.h | 4 ++++
arch/powerpc/kernel/head_85xx.S | 10 ++++++----
2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/include/asm/pgtable-types.h b/arch/powerpc/include/asm/pgtable-types.h
index 082c85cc09b1..db965d98e0ae 100644
--- a/arch/powerpc/include/asm/pgtable-types.h
+++ b/arch/powerpc/include/asm/pgtable-types.h
@@ -49,7 +49,11 @@ static inline unsigned long pud_val(pud_t x)
#endif /* CONFIG_PPC64 */

/* PGD level */
+#if defined(CONFIG_PPC_E500) && defined(CONFIG_PTE_64BIT)
+typedef struct { unsigned long long pgd; } pgd_t;
+#else
typedef struct { unsigned long pgd; } pgd_t;
+#endif
#define __pgd(x) ((pgd_t) { (x) })
static inline unsigned long pgd_val(pgd_t x)
{
diff --git a/arch/powerpc/kernel/head_85xx.S b/arch/powerpc/kernel/head_85xx.S
index 39724ff5ae1f..a305244afc9f 100644
--- a/arch/powerpc/kernel/head_85xx.S
+++ b/arch/powerpc/kernel/head_85xx.S
@@ -307,8 +307,9 @@ set_ivor:
#ifdef CONFIG_PTE_64BIT
#ifdef CONFIG_HUGETLB_PAGE
#define FIND_PTE \
- rlwinm r12, r10, 13, 19, 29; /* Compute pgdir/pmd offset */ \
- lwzx r11, r12, r11; /* Get pgd/pmd entry */ \
+ rlwinm r12, r10, 14, 18, 28; /* Compute pgdir/pmd offset */ \
+ add r12, r11, r12; \
+ lwz r11, 4(r12); /* Get pgd/pmd entry */ \
rlwinm. r12, r11, 0, 0, 20; /* Extract pt base address */ \
blt 1000f; /* Normal non-huge page */ \
beq 2f; /* Bail if no table */ \
@@ -321,8 +322,9 @@ set_ivor:
1001: lwz r11, 4(r12); /* Get pte entry */
#else
#define FIND_PTE \
- rlwinm r12, r10, 13, 19, 29; /* Compute pgdir/pmd offset */ \
- lwzx r11, r12, r11; /* Get pgd/pmd entry */ \
+ rlwinm r12, r10, 14, 18, 28; /* Compute pgdir/pmd offset */ \
+ add r12, r11, r12; \
+ lwz r11, 4(r12); /* Get pgd/pmd entry */ \
rlwinm. r12, r11, 0, 0, 20; /* Extract pt base address */ \
beq 2f; /* Bail if no table */ \
rlwimi r12, r10, 23, 20, 28; /* Compute pte address */ \
--
2.44.0