[PATCH v5 10/21] arm64: mm: provide idmap pointer to cpu_replace_ttbr1()

Ard Biesheuvel
2022-06-24T15:11:28Z

In preparation for changing the way we initialize the permanent ID map,
update cpu_replace_ttbr1() so we can use it with the initial ID map as
well.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/arm64/include/asm/mmu_context.h | 13 +++++++++----
arch/arm64/kernel/cpufeature.c | 2 +-
arch/arm64/kernel/suspend.c | 2 +-
arch/arm64/mm/kasan_init.c | 4 ++--
arch/arm64/mm/mmu.c | 2 +-
5 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h
index 7b387c3b312a..c7ccd82db1d2 100644
--- a/arch/arm64/include/asm/mmu_context.h
+++ b/arch/arm64/include/asm/mmu_context.h
@@ -105,13 +105,18 @@ static inline void cpu_uninstall_idmap(void)
cpu_switch_mm(mm->pgd, mm);
}

-static inline void cpu_install_idmap(void)
+static inline void __cpu_install_idmap(pgd_t *idmap)
{
cpu_set_reserved_ttbr0();
local_flush_tlb_all();
cpu_set_idmap_tcr_t0sz();

- cpu_switch_mm(lm_alias(idmap_pg_dir), &init_mm);
+ cpu_switch_mm(lm_alias(idmap), &init_mm);
+}
+
+static inline void cpu_install_idmap(void)
+{
+ __cpu_install_idmap(idmap_pg_dir);
}

/*
@@ -142,7 +147,7 @@ static inline void cpu_install_ttbr0(phys_addr_t ttbr0, unsigned long t0sz)
* Atomically replaces the active TTBR1_EL1 PGD with a new VA-compatible PGD,
* avoiding the possibility of conflicting TLB entries being allocated.
*/
-static inline void __nocfi cpu_replace_ttbr1(pgd_t *pgdp)
+static inline void __nocfi cpu_replace_ttbr1(pgd_t *pgdp, pgd_t *idmap)
{
typedef void (ttbr_replace_func)(phys_addr_t);
extern ttbr_replace_func idmap_cpu_replace_ttbr1;
@@ -165,7 +170,7 @@ static inline void __nocfi cpu_replace_ttbr1(pgd_t *pgdp)

replace_phys = (void *)__pa_symbol(function_nocfi(idmap_cpu_replace_ttbr1));

- cpu_install_idmap();
+ __cpu_install_idmap(idmap);
replace_phys(ttbr1);
cpu_uninstall_idmap();
}
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 145b43c6c651..98b48d9069a7 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -3266,7 +3266,7 @@ subsys_initcall_sync(init_32bit_el0_mask);

static void __maybe_unused cpu_enable_cnp(struct arm64_cpu_capabilities const *cap)
{
- cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
+ cpu_replace_ttbr1(lm_alias(swapper_pg_dir), idmap_pg_dir);
}

/*
diff --git a/arch/arm64/kernel/suspend.c b/arch/arm64/kernel/suspend.c
index 2b0887e58a7c..9135fe0f3df5 100644
--- a/arch/arm64/kernel/suspend.c
+++ b/arch/arm64/kernel/suspend.c
@@ -52,7 +52,7 @@ void notrace __cpu_suspend_exit(void)

/* Restore CnP bit in TTBR1_EL1 */
if (system_supports_cnp())
- cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
+ cpu_replace_ttbr1(lm_alias(swapper_pg_dir), idmap_pg_dir);

/*
* PSTATE was not saved over suspend/resume, re-enable any detected
diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
index c12cd700598f..e969e68de005 100644
--- a/arch/arm64/mm/kasan_init.c
+++ b/arch/arm64/mm/kasan_init.c
@@ -236,7 +236,7 @@ static void __init kasan_init_shadow(void)
*/
memcpy(tmp_pg_dir, swapper_pg_dir, sizeof(tmp_pg_dir));
dsb(ishst);
- cpu_replace_ttbr1(lm_alias(tmp_pg_dir));
+ cpu_replace_ttbr1(lm_alias(tmp_pg_dir), idmap_pg_dir);

clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END);

@@ -280,7 +280,7 @@ static void __init kasan_init_shadow(void)
PAGE_KERNEL_RO));

memset(kasan_early_shadow_page, KASAN_SHADOW_INIT, PAGE_SIZE);
- cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
+ cpu_replace_ttbr1(lm_alias(swapper_pg_dir), idmap_pg_dir);
}

static void __init kasan_init_depth(void)
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 3be0e9f69406..488628f07b89 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -780,7 +780,7 @@ void __init paging_init(void)

pgd_clear_fixmap();

- cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
+ cpu_replace_ttbr1(lm_alias(swapper_pg_dir), idmap_pg_dir);
init_mm.pgd = swapper_pg_dir;

memblock_phys_free(__pa_symbol(init_pg_dir),