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| author | Jens Axboe <axboe@kernel.dk> | 2022-07-24 18:41:03 -0600 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2022-07-24 18:41:03 -0600 |
| commit | 4effe18fc0da27ae5d51a702841e87fa13b8a32d (patch) | |
| tree | 468f353a3713c93b27e7b2c262efd747e66ff199 /arch/x86/entry/calling.h | |
| parent | Merge branch 'io_uring-zerocopy-send' of git://git.kernel.org/pub/scm/linux/k... (diff) | |
| parent | io_uring: ensure REQ_F_ISREG is set async offload (diff) | |
| download | linux-4effe18fc0da27ae5d51a702841e87fa13b8a32d.tar.gz linux-4effe18fc0da27ae5d51a702841e87fa13b8a32d.zip | |
Merge branch 'for-5.20/io_uring' into for-5.20/io_uring-zerocopy-send
* for-5.20/io_uring: (716 commits)
io_uring: ensure REQ_F_ISREG is set async offload
net: fix compat pointer in get_compat_msghdr()
io_uring: Don't require reinitable percpu_ref
io_uring: fix types in io_recvmsg_multishot_overflow
io_uring: Use atomic_long_try_cmpxchg in __io_account_mem
io_uring: support multishot in recvmsg
net: copy from user before calling __get_compat_msghdr
net: copy from user before calling __copy_msghdr
io_uring: support 0 length iov in buffer select in compat
io_uring: fix multishot ending when not polled
io_uring: add netmsg cache
io_uring: impose max limit on apoll cache
io_uring: add abstraction around apoll cache
io_uring: move apoll cache to poll.c
io_uring: consolidate hash_locked io-wq handling
io_uring: clear REQ_F_HASH_LOCKED on hash removal
io_uring: don't race double poll setting REQ_F_ASYNC_DATA
io_uring: don't miss setting REQ_F_DOUBLE_POLL
io_uring: disable multishot recvmsg
io_uring: only trace one of complete or overflow
...
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'arch/x86/entry/calling.h')
| -rw-r--r-- | arch/x86/entry/calling.h | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h index 29b36e9e4e74..f6907627172b 100644 --- a/arch/x86/entry/calling.h +++ b/arch/x86/entry/calling.h @@ -7,6 +7,8 @@ #include <asm/asm-offsets.h> #include <asm/processor-flags.h> #include <asm/ptrace-abi.h> +#include <asm/msr.h> +#include <asm/nospec-branch.h> /* @@ -283,6 +285,66 @@ For 32-bit we have the following conventions - kernel is built with #endif /* + * IBRS kernel mitigation for Spectre_v2. + * + * Assumes full context is established (PUSH_REGS, CR3 and GS) and it clobbers + * the regs it uses (AX, CX, DX). Must be called before the first RET + * instruction (NOTE! UNTRAIN_RET includes a RET instruction) + * + * The optional argument is used to save/restore the current value, + * which is used on the paranoid paths. + * + * Assumes x86_spec_ctrl_{base,current} to have SPEC_CTRL_IBRS set. + */ +.macro IBRS_ENTER save_reg +#ifdef CONFIG_CPU_IBRS_ENTRY + ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_KERNEL_IBRS + movl $MSR_IA32_SPEC_CTRL, %ecx + +.ifnb \save_reg + rdmsr + shl $32, %rdx + or %rdx, %rax + mov %rax, \save_reg + test $SPEC_CTRL_IBRS, %eax + jz .Ldo_wrmsr_\@ + lfence + jmp .Lend_\@ +.Ldo_wrmsr_\@: +.endif + + movq PER_CPU_VAR(x86_spec_ctrl_current), %rdx + movl %edx, %eax + shr $32, %rdx + wrmsr +.Lend_\@: +#endif +.endm + +/* + * Similar to IBRS_ENTER, requires KERNEL GS,CR3 and clobbers (AX, CX, DX) + * regs. Must be called after the last RET. + */ +.macro IBRS_EXIT save_reg +#ifdef CONFIG_CPU_IBRS_ENTRY + ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_KERNEL_IBRS + movl $MSR_IA32_SPEC_CTRL, %ecx + +.ifnb \save_reg + mov \save_reg, %rdx +.else + movq PER_CPU_VAR(x86_spec_ctrl_current), %rdx + andl $(~SPEC_CTRL_IBRS), %edx +.endif + + movl %edx, %eax + shr $32, %rdx + wrmsr +.Lend_\@: +#endif +.endm + +/* * Mitigate Spectre v1 for conditional swapgs code paths. * * FENCE_SWAPGS_USER_ENTRY is used in the user entry swapgs code path, to |