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Subject[patch V2 1/5] x86/kaiser: Respect disabled CPU features
PAGE_NX and PAGE_GLOBAL might be not supported or disabled on the command
line, but KAISER sets them unconditionally.

Add proper protection against that.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/include/asm/pgtable_64.h | 3 ++-
arch/x86/mm/kaiser.c | 12 +++++++++++-
2 files changed, 13 insertions(+), 2 deletions(-)

--- a/arch/x86/include/asm/pgtable_64.h
+++ b/arch/x86/include/asm/pgtable_64.h
@@ -222,7 +222,8 @@ static inline pgd_t kaiser_set_shadow_pg
* wrong CR3 value, userspace will crash
* instead of running.
*/
- pgd.pgd |= _PAGE_NX;
+ if (__supported_pte_mask & _PAGE_NX)
+ pgd.pgd |= _PAGE_NX;
}
} else if (pgd_userspace_access(*pgdp)) {
/*
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -42,6 +42,8 @@

#define KAISER_WALK_ATOMIC 0x1

+static pteval_t kaiser_pte_mask __ro_after_init = ~(_PAGE_NX | _PAGE_GLOBAL);
+
/*
* At runtime, the only things we map are some things for CPU
* hotplug, and stacks for new processes. No two CPUs will ever
@@ -244,11 +246,14 @@ static pte_t *kaiser_shadow_pagetable_wa
int kaiser_add_user_map(const void *__start_addr, unsigned long size,
unsigned long flags)
{
- pte_t *pte;
unsigned long start_addr = (unsigned long)__start_addr;
unsigned long address = start_addr & PAGE_MASK;
unsigned long end_addr = PAGE_ALIGN(start_addr + size);
unsigned long target_address;
+ pte_t *pte;
+
+ /* Clear not supported bits */
+ flags &= kaiser_pte_mask;

for (; address < end_addr; address += PAGE_SIZE) {
target_address = get_pa_from_kernel_map(address);
@@ -308,6 +313,11 @@ static void __init kaiser_init_all_pgds(
pgd_t *pgd;
int i;

+ if (__supported_pte_mask & _PAGE_NX)
+ kaiser_pte_mask |= _PAGE_NX;
+ if (boot_cpu_has(X86_FEATURE_PGE))
+ kaiser_pte_mask |= _PAGE_GLOBAL;
+
pgd = kernel_to_shadow_pgdp(pgd_offset_k(0UL));
for (i = PTRS_PER_PGD / 2; i < PTRS_PER_PGD; i++) {
/*

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