[PATCH] x86/pti: Make X86_BUG_CPU_SECURE_MODE_PTI an X86_FEATURE

From: Borislav Petkov
Date: Tue Dec 12 2017 - 14:00:53 EST

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From: Borislav Petkov <bp@xxxxxxx>

... to denote that we have enabled page table isolation. Which is not a
bug but a feature! :-)

Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirsky <luto@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: keescook@xxxxxxxxxx
Cc: hughd@xxxxxxxxxx
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: David Laight <David.Laight@xxxxxxxxxx>
Cc: Eduardo Valentin <eduval@xxxxxxxxxx>
Cc: aliguori@xxxxxxxxxx
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: daniel.gruss@xxxxxxxxxxxxxx
---
arch/x86/entry/calling.h | 8 ++++----
arch/x86/include/asm/cpufeatures.h | 3 +--
arch/x86/include/asm/tlbflush.h | 6 +++---
arch/x86/kernel/cpu/common.c | 2 +-
arch/x86/kernel/ldt.c | 2 +-
arch/x86/mm/dump_pagetables.c | 4 ++--
arch/x86/mm/init.c | 2 +-
arch/x86/mm/pti.c | 6 +++---
arch/x86/mm/tlb.c | 2 +-
9 files changed, 17 insertions(+), 18 deletions(-)

diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h
index 393a5bf190b7..45a63e00a6af 100644
--- a/arch/x86/entry/calling.h
+++ b/arch/x86/entry/calling.h
@@ -212,7 +212,7 @@ For 32-bit we have the following conventions - kernel is built with
.endm

.macro SWITCH_TO_KERNEL_CR3 scratch_reg:req
- ALTERNATIVE "jmp .Lend_\@", "", X86_BUG_CPU_SECURE_MODE_PTI
+ ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_PTI
mov %cr3, \scratch_reg
ADJUST_KERNEL_CR3 \scratch_reg
mov \scratch_reg, %cr3
@@ -223,7 +223,7 @@ For 32-bit we have the following conventions - kernel is built with
PER_CPU_VAR(cpu_tlbstate) + TLB_STATE_user_pcid_flush_mask

.macro SWITCH_TO_USER_CR3_NOSTACK scratch_reg:req scratch_reg2:req
- ALTERNATIVE "jmp .Lend_\@", "", X86_BUG_CPU_SECURE_MODE_PTI
+ ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_PTI
mov %cr3, \scratch_reg

ALTERNATIVE "jmp .Lwrcr3_\@", "", X86_FEATURE_PCID
@@ -259,7 +259,7 @@ For 32-bit we have the following conventions - kernel is built with
.endm

.macro SAVE_AND_SWITCH_TO_KERNEL_CR3 scratch_reg:req save_reg:req
- ALTERNATIVE "jmp .Ldone_\@", "", X86_BUG_CPU_SECURE_MODE_PTI
+ ALTERNATIVE "jmp .Ldone_\@", "", X86_FEATURE_PTI
movq %cr3, \scratch_reg
movq \scratch_reg, \save_reg
/*
@@ -282,7 +282,7 @@ For 32-bit we have the following conventions - kernel is built with
.endm

.macro RESTORE_CR3 scratch_reg:req save_reg:req
- ALTERNATIVE "jmp .Lend_\@", "", X86_BUG_CPU_SECURE_MODE_PTI
+ ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_PTI

ALTERNATIVE "jmp .Lwrcr3_\@", "", X86_FEATURE_PCID

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index f8c2bd42ec48..df7e474b470b 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -198,10 +198,10 @@
#define X86_FEATURE_CAT_L2 ( 7*32+ 5) /* Cache Allocation Technology L2 */
#define X86_FEATURE_CDP_L3 ( 7*32+ 6) /* Code and Data Prioritization L3 */
#define X86_FEATURE_INVPCID_SINGLE ( 7*32+ 7) /* Effectively INVPCID && CR4.PCIDE=1 */
-
#define X86_FEATURE_HW_PSTATE ( 7*32+ 8) /* AMD HW-PState */
#define X86_FEATURE_PROC_FEEDBACK ( 7*32+ 9) /* AMD ProcFeedbackInterface */
#define X86_FEATURE_SME ( 7*32+10) /* AMD Secure Memory Encryption */
+#define X86_FEATURE_PTI ( 7*32+11) /* Kernel Page Table Isolation enabled */

#define X86_FEATURE_INTEL_PPIN ( 7*32+14) /* Intel Processor Inventory Number */
#define X86_FEATURE_INTEL_PT ( 7*32+15) /* Intel Processor Trace */
@@ -342,6 +342,5 @@
#define X86_BUG_MONITOR X86_BUG(12) /* IPI required to wake up remote CPU */
#define X86_BUG_AMD_E400 X86_BUG(13) /* CPU is among the affected by Erratum 400 */
#define X86_BUG_CPU_INSECURE X86_BUG(14) /* CPU is insecure and needs kernel page table isolation */
-#define X86_BUG_CPU_SECURE_MODE_PTI X86_BUG(15) /* Kernel Page Table Isolation enabled*/

#endif /* _ASM_X86_CPUFEATURES_H */
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
index a97f000caf2f..8590aa954a1d 100644
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -333,7 +333,7 @@ static inline void invalidate_user_asid(u16 asid)
if (!cpu_feature_enabled(X86_FEATURE_PCID))
return;

- if (!static_cpu_has_bug(X86_BUG_CPU_SECURE_MODE_PTI))
+ if (!static_cpu_has(X86_FEATURE_PTI))
return;

__set_bit(kern_pcid(asid),
@@ -399,7 +399,7 @@ static inline void __native_flush_tlb_single(unsigned long addr)

asm volatile("invlpg (%0)" ::"r" (addr) : "memory");

- if (!static_cpu_has_bug(X86_BUG_CPU_SECURE_MODE_PTI))
+ if (!static_cpu_has(X86_FEATURE_PTI))
return;

/*
@@ -435,7 +435,7 @@ static inline void __flush_tlb_one(unsigned long addr)
count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ONE);
__flush_tlb_single(addr);

- if (!static_cpu_has_bug(X86_BUG_CPU_SECURE_MODE_PTI))
+ if (!static_cpu_has(X86_FEATURE_PTI))
return;

/*
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 7b9d87107950..7b2988e521a7 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1456,7 +1456,7 @@ void syscall_init(void)
(entry_SYSCALL_64_trampoline - _entry_trampoline);

wrmsr(MSR_STAR, 0, (__USER32_CS << 16) | __KERNEL_CS);
- if (static_cpu_has_bug(X86_BUG_CPU_SECURE_MODE_PTI))
+ if (static_cpu_has(X86_FEATURE_PTI))
wrmsrl(MSR_LSTAR, SYSCALL64_entry_trampoline);
else
wrmsrl(MSR_LSTAR, (unsigned long)entry_SYSCALL_64);
diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c
index a10286342e05..b88dcaf7249e 100644
--- a/arch/x86/kernel/ldt.c
+++ b/arch/x86/kernel/ldt.c
@@ -53,7 +53,7 @@ static void set_ldt_and_map(struct ldt_struct *ldt)
void *fixva;
int idx, i;

- if (!static_cpu_has_bug(X86_BUG_CPU_SECURE_MODE_PTI)) {
+ if (!static_cpu_has(X86_FEATURE_PTI)) {
set_ldt(ldt->entries, ldt->nr_entries);
return;
}
diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c
index e5a2df886130..b740c2b100fe 100644
--- a/arch/x86/mm/dump_pagetables.c
+++ b/arch/x86/mm/dump_pagetables.c
@@ -504,7 +504,7 @@ void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd)
void ptdump_walk_pgd_level_debugfs(struct seq_file *m, pgd_t *pgd, bool user)
{
#ifdef CONFIG_PAGE_TABLE_ISOLATION
- if (user && static_cpu_has_bug(X86_BUG_CPU_SECURE_MODE_PTI))
+ if (user && static_cpu_has(X86_FEATURE_PTI))
pgd = kernel_to_user_pgdp(pgd);
#endif
ptdump_walk_pgd_level_core(m, pgd, false, false);
@@ -516,7 +516,7 @@ static void ptdump_walk_user_pgd_level_checkwx(void)
#ifdef CONFIG_PAGE_TABLE_ISOLATION
pgd_t *pgd = (pgd_t *) &init_top_pgt;

- if (!static_cpu_has_bug(X86_BUG_CPU_SECURE_MODE_PTI))
+ if (!static_cpu_has(X86_FEATURE_PTI))
return;

pr_info("x86/mm: Checking user space page tables\n");
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 3fb7806c6806..80259ad8c386 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -164,7 +164,7 @@ static int page_size_mask;

static void enable_global_pages(void)
{
- if (!static_cpu_has_bug(X86_BUG_CPU_SECURE_MODE_PTI))
+ if (!static_cpu_has(X86_FEATURE_PTI))
__supported_pte_mask |= _PAGE_GLOBAL;
}

diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c
index 1f8114689528..6294c44a60cf 100644
--- a/arch/x86/mm/pti.c
+++ b/arch/x86/mm/pti.c
@@ -79,7 +79,7 @@ void __init pti_check_boottime_disable(void)

enable:
if (enable)
- setup_force_cpu_bug(X86_BUG_CPU_SECURE_MODE_PTI);
+ setup_force_cpu_cap(X86_FEATURE_PTI);
}

/*
@@ -89,7 +89,7 @@ void __init pti_check_boottime_disable(void)
*/
pgd_t pti_set_user_pgd(pgd_t *pgdp, pgd_t pgd)
{
- if (!static_cpu_has_bug(X86_BUG_CPU_SECURE_MODE_PTI))
+ if (!static_cpu_has(X86_FEATURE_PTI))
return pgd;

if (pgdp_maps_userspace(pgdp)) {
@@ -272,7 +272,7 @@ static void __init pti_clone_entry_text(void)
*/
void __init pti_init(void)
{
- if (!static_cpu_has_bug(X86_BUG_CPU_SECURE_MODE_PTI))
+ if (!static_cpu_has(X86_FEATURE_PTI))
return;

pr_info("enabled\n");
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 7982d873a6ac..a1561957dccb 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -42,7 +42,7 @@ void clear_asid_other(void)
* This is only expected to be set if we have disabled
* kernel _PAGE_GLOBAL pages.
*/
- if (!static_cpu_has_bug(X86_BUG_CPU_SECURE_MODE_PTI)) {
+ if (!static_cpu_has(X86_FEATURE_PTI)) {
WARN_ON_ONCE(1);
return;
}
--
2.13.0

Next message: Linus Torvalds: "Re: [patch 13/16] x86/ldt: Introduce LDT write fault handler"
Previous message: Dan Murphy: "[PATCH v3 6/6] leds: lp8860: Various fixes to align with LED framework"
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