diff options
Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.9.21/0030-kaiser-use-ALTERNATIVE-instead-of-x86_cr3_pcid_noflu.patch')
| -rw-r--r-- | common/recipes-kernel/linux/linux-yocto-4.9.21/0030-kaiser-use-ALTERNATIVE-instead-of-x86_cr3_pcid_noflu.patch | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0030-kaiser-use-ALTERNATIVE-instead-of-x86_cr3_pcid_noflu.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0030-kaiser-use-ALTERNATIVE-instead-of-x86_cr3_pcid_noflu.patch new file mode 100644 index 00000000..9c34147d --- /dev/null +++ b/common/recipes-kernel/linux/linux-yocto-4.9.21/0030-kaiser-use-ALTERNATIVE-instead-of-x86_cr3_pcid_noflu.patch @@ -0,0 +1,137 @@ +From 9a72e20b9aaf74010d4426ec95e58c262161465e Mon Sep 17 00:00:00 2001 +From: Hugh Dickins <hughd@google.com> +Date: Tue, 3 Oct 2017 20:49:04 -0700 +Subject: [PATCH 030/102] kaiser: use ALTERNATIVE instead of + x86_cr3_pcid_noflush + +Now that we're playing the ALTERNATIVE game, use that more efficient +method: instead of user-mapping an extra page, and reading an extra +cacheline each time for x86_cr3_pcid_noflush. + +Neel has found that __stringify(bts $X86_CR3_PCID_NOFLUSH_BIT, %rax) +is a working substitute for the "bts $63, %rax" in these ALTERNATIVEs; +but the one line with $63 in looks clearer, so let's stick with that. + +Worried about what happens with an ALTERNATIVE between the jump and +jump label in another ALTERNATIVE? I was, but have checked the +combinations in SWITCH_KERNEL_CR3_NO_STACK at entry_SYSCALL_64, +and it does a good job. + +Signed-off-by: Hugh Dickins <hughd@google.com> +Acked-by: Jiri Kosina <jkosina@suse.cz> +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +--- + arch/x86/entry/entry_64.S | 7 ++++--- + arch/x86/include/asm/kaiser.h | 6 +++--- + arch/x86/mm/kaiser.c | 11 +---------- + 3 files changed, 8 insertions(+), 16 deletions(-) + +diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S +index bbb38ac..d4ba81e 100644 +--- a/arch/x86/entry/entry_64.S ++++ b/arch/x86/entry/entry_64.S +@@ -1084,7 +1084,8 @@ ENTRY(paranoid_entry) + jz 2f + orl $2, %ebx + andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), %rax +- orq x86_cr3_pcid_noflush, %rax ++ /* If PCID enabled, set X86_CR3_PCID_NOFLUSH_BIT */ ++ ALTERNATIVE "", "bts $63, %rax", X86_FEATURE_PCID + movq %rax, %cr3 + 2: + #endif +@@ -1342,7 +1343,7 @@ ENTRY(nmi) + /* %rax is saved above, so OK to clobber here */ + ALTERNATIVE "jmp 2f", "movq %cr3, %rax", X86_FEATURE_KAISER + /* If PCID enabled, NOFLUSH now and NOFLUSH on return */ +- orq x86_cr3_pcid_noflush, %rax ++ ALTERNATIVE "", "bts $63, %rax", X86_FEATURE_PCID + pushq %rax + /* mask off "user" bit of pgd address and 12 PCID bits: */ + andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), %rax +@@ -1586,7 +1587,7 @@ end_repeat_nmi: + /* %rax is saved above, so OK to clobber here */ + ALTERNATIVE "jmp 2f", "movq %cr3, %rax", X86_FEATURE_KAISER + /* If PCID enabled, NOFLUSH now and NOFLUSH on return */ +- orq x86_cr3_pcid_noflush, %rax ++ ALTERNATIVE "", "bts $63, %rax", X86_FEATURE_PCID + pushq %rax + /* mask off "user" bit of pgd address and 12 PCID bits: */ + andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), %rax +diff --git a/arch/x86/include/asm/kaiser.h b/arch/x86/include/asm/kaiser.h +index 96643a9..906150d 100644 +--- a/arch/x86/include/asm/kaiser.h ++++ b/arch/x86/include/asm/kaiser.h +@@ -25,7 +25,8 @@ + .macro _SWITCH_TO_KERNEL_CR3 reg + movq %cr3, \reg + andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), \reg +-orq x86_cr3_pcid_noflush, \reg ++/* If PCID enabled, set X86_CR3_PCID_NOFLUSH_BIT */ ++ALTERNATIVE "", "bts $63, \reg", X86_FEATURE_PCID + movq \reg, %cr3 + .endm + +@@ -39,7 +40,7 @@ movq \reg, %cr3 + movq %cr3, \reg + orq PER_CPU_VAR(x86_cr3_pcid_user), \reg + js 9f +-/* FLUSH this time, reset to NOFLUSH for next time (if PCID enabled) */ ++/* If PCID enabled, FLUSH this time, reset to NOFLUSH for next time */ + movb \regb, PER_CPU_VAR(x86_cr3_pcid_user+7) + 9: + movq \reg, %cr3 +@@ -90,7 +91,6 @@ movq PER_CPU_VAR(unsafe_stack_register_backup), %rax + */ + DECLARE_PER_CPU_USER_MAPPED(unsigned long, unsafe_stack_register_backup); + +-extern unsigned long x86_cr3_pcid_noflush; + DECLARE_PER_CPU(unsigned long, x86_cr3_pcid_user); + + extern char __per_cpu_user_mapped_start[], __per_cpu_user_mapped_end[]; +diff --git a/arch/x86/mm/kaiser.c b/arch/x86/mm/kaiser.c +index 1840aa0..b8aa9ad 100644 +--- a/arch/x86/mm/kaiser.c ++++ b/arch/x86/mm/kaiser.c +@@ -31,7 +31,6 @@ DEFINE_PER_CPU_USER_MAPPED(unsigned long, unsafe_stack_register_backup); + * This is also handy because systems that do not support PCIDs + * just end up or'ing a 0 into their CR3, which does no harm. + */ +-unsigned long x86_cr3_pcid_noflush __read_mostly; + DEFINE_PER_CPU(unsigned long, x86_cr3_pcid_user); + + /* +@@ -356,10 +355,6 @@ void __init kaiser_init(void) + kaiser_add_user_map_early(&debug_idt_table, + sizeof(gate_desc) * NR_VECTORS, + __PAGE_KERNEL); +- +- kaiser_add_user_map_early(&x86_cr3_pcid_noflush, +- sizeof(x86_cr3_pcid_noflush), +- __PAGE_KERNEL); + } + + /* Add a mapping to the shadow mapping, and synchronize the mappings */ +@@ -433,18 +428,14 @@ pgd_t kaiser_set_shadow_pgd(pgd_t *pgdp, pgd_t pgd) + + void kaiser_setup_pcid(void) + { +- unsigned long kern_cr3 = 0; + unsigned long user_cr3 = KAISER_SHADOW_PGD_OFFSET; + +- if (this_cpu_has(X86_FEATURE_PCID)) { +- kern_cr3 |= X86_CR3_PCID_KERN_NOFLUSH; ++ if (this_cpu_has(X86_FEATURE_PCID)) + user_cr3 |= X86_CR3_PCID_USER_NOFLUSH; +- } + /* + * These variables are used by the entry/exit + * code to change PCID and pgd and TLB flushing. + */ +- x86_cr3_pcid_noflush = kern_cr3; + this_cpu_write(x86_cr3_pcid_user, user_cr3); + } + +-- +2.7.4 + |