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Date: Tue, 29 May 2018 12:37:41 +0800
From: YaoJun <yaojun8558363@...il.com>
To: kernel-hardening@...ts.openwall.com
Cc: linux-kernel@...r.kernel.org,
linux-security-module@...r.kernel.org,
jmorris@...ei.org
Subject: [PATCH 1/4] migrate swapper_pg_dir
Currently, __enable_mmu() uses swapper_pg_dir directly.
To migrate swapper_pg_dir, we need to pass it as an
argument to __enable_mmu(). At the same time,
__pa_swapper_pg_dir is introduced to save physical
address of swapper_pg_dir. By changing its value, we
can migrate swapper_pg_dir.
---
arch/arm64/include/asm/mmu_context.h | 4 +---
arch/arm64/include/asm/pgtable.h | 1 +
arch/arm64/kernel/cpufeature.c | 2 +-
arch/arm64/kernel/head.S | 10 ++++++----
arch/arm64/kernel/hibernate.c | 2 +-
arch/arm64/kernel/sleep.S | 2 ++
arch/arm64/mm/kasan_init.c | 4 ++--
arch/arm64/mm/mmu.c | 8 ++++++--
8 files changed, 20 insertions(+), 13 deletions(-)
diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h
index 39ec0b8a689e..3eddb871f251 100644
--- a/arch/arm64/include/asm/mmu_context.h
+++ b/arch/arm64/include/asm/mmu_context.h
@@ -141,14 +141,12 @@ static inline void cpu_install_idmap(void)
* 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 cpu_replace_ttbr1(pgd_t *pgdp)
+static inline void cpu_replace_ttbr1(phys_addr_t pgd_phys)
{
typedef void (ttbr_replace_func)(phys_addr_t);
extern ttbr_replace_func idmap_cpu_replace_ttbr1;
ttbr_replace_func *replace_phys;
- phys_addr_t pgd_phys = virt_to_phys(pgdp);
-
replace_phys = (void *)__pa_symbol(idmap_cpu_replace_ttbr1);
cpu_install_idmap();
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 7c4c8f318ba9..14ba344b1af7 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -722,6 +722,7 @@ extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
extern pgd_t swapper_pg_end[];
extern pgd_t idmap_pg_dir[PTRS_PER_PGD];
extern pgd_t tramp_pg_dir[PTRS_PER_PGD];
+extern phys_addr_t __pa_swapper_pg_dir;
/*
* Encode and decode a swap entry:
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 9d1b06d67c53..5b9448688d80 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -917,7 +917,7 @@ kpti_install_ng_mappings(const struct arm64_cpu_capabilities *__unused)
remap_fn = (void *)__pa_symbol(idmap_kpti_install_ng_mappings);
cpu_install_idmap();
- remap_fn(cpu, num_online_cpus(), __pa_symbol(swapper_pg_dir));
+ remap_fn(cpu, num_online_cpus(), __pa_swapper_pg_dir);
cpu_uninstall_idmap();
if (!cpu)
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index b0853069702f..e3bb44b4b6c6 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -706,6 +706,8 @@ secondary_startup:
* Common entry point for secondary CPUs.
*/
bl __cpu_setup // initialise processor
+ adrp x25, idmap_pg_dir
+ ldr_l x26, __pa_swapper_pg_dir
bl __enable_mmu
ldr x8, =__secondary_switched
br x8
@@ -761,10 +763,8 @@ ENTRY(__enable_mmu)
cmp x2, #ID_AA64MMFR0_TGRAN_SUPPORTED
b.ne __no_granule_support
update_early_cpu_boot_status 0, x1, x2
- adrp x1, idmap_pg_dir
- adrp x2, swapper_pg_dir
- phys_to_ttbr x3, x1
- phys_to_ttbr x4, x2
+ phys_to_ttbr x3, x25
+ phys_to_ttbr x4, x26
msr ttbr0_el1, x3 // load TTBR0
msr ttbr1_el1, x4 // load TTBR1
isb
@@ -823,6 +823,8 @@ __primary_switch:
mrs x20, sctlr_el1 // preserve old SCTLR_EL1 value
#endif
+ adrp x25, idmap_pg_dir
+ adrp x26, swapper_pg_dir
bl __enable_mmu
#ifdef CONFIG_RELOCATABLE
bl __relocate_kernel
diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c
index 1ec5f28c39fc..12948949202c 100644
--- a/arch/arm64/kernel/hibernate.c
+++ b/arch/arm64/kernel/hibernate.c
@@ -125,7 +125,7 @@ int arch_hibernation_header_save(void *addr, unsigned int max_size)
return -EOVERFLOW;
arch_hdr_invariants(&hdr->invariants);
- hdr->ttbr1_el1 = __pa_symbol(swapper_pg_dir);
+ hdr->ttbr1_el1 = __pa_swapper_pg_dir;
hdr->reenter_kernel = _cpu_resume;
/* We can't use __hyp_get_vectors() because kvm may still be loaded */
diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S
index bebec8ef9372..860d46395be1 100644
--- a/arch/arm64/kernel/sleep.S
+++ b/arch/arm64/kernel/sleep.S
@@ -101,6 +101,8 @@ ENTRY(cpu_resume)
bl el2_setup // if in EL2 drop to EL1 cleanly
bl __cpu_setup
/* enable the MMU early - so we can access sleep_save_stash by va */
+ adrp x25, idmap_pg_dir
+ ldr_l x26, __pa_swapper_pg_dir
bl __enable_mmu
ldr x8, =_cpu_resume
br x8
diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
index 12145874c02b..dd4f28c19165 100644
--- a/arch/arm64/mm/kasan_init.c
+++ b/arch/arm64/mm/kasan_init.c
@@ -199,7 +199,7 @@ void __init kasan_init(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(__pa_symbol(tmp_pg_dir));
clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END);
@@ -236,7 +236,7 @@ void __init kasan_init(void)
pfn_pte(sym_to_pfn(kasan_zero_page), PAGE_KERNEL_RO));
memset(kasan_zero_page, 0, PAGE_SIZE);
- cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
+ cpu_replace_ttbr1(__pa_swapper_pg_dir);
/* At this point kasan is fully initialized. Enable error messages */
init_task.kasan_depth = 0;
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 2dbb2c9f1ec1..41eee333f91a 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -55,6 +55,8 @@ u64 idmap_ptrs_per_pgd = PTRS_PER_PGD;
u64 kimage_voffset __ro_after_init;
EXPORT_SYMBOL(kimage_voffset);
+phys_addr_t __pa_swapper_pg_dir;
+
/*
* Empty_zero_page is a special page that is used for zero-initialized data
* and COW.
@@ -631,6 +633,8 @@ void __init paging_init(void)
phys_addr_t pgd_phys = early_pgtable_alloc();
pgd_t *pgdp = pgd_set_fixmap(pgd_phys);
+ __pa_swapper_pg_dir = __pa_symbol(swapper_pg_dir);
+
map_kernel(pgdp);
map_mem(pgdp);
@@ -642,9 +646,9 @@ void __init paging_init(void)
*
* To do this we need to go via a temporary pgd.
*/
- cpu_replace_ttbr1(__va(pgd_phys));
+ cpu_replace_ttbr1(pgd_phys);
memcpy(swapper_pg_dir, pgdp, PGD_SIZE);
- cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
+ cpu_replace_ttbr1(__pa_swapper_pg_dir);
pgd_clear_fixmap();
memblock_free(pgd_phys, PAGE_SIZE);
--
2.17.0
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