diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-03-31 11:26:22 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-03-31 11:26:22 -0700 |
commit | d0be2d53c7df80753746f564220279ee4b725632 (patch) | |
tree | 602bd985e3ef2cd4217a2fd92f1269359b8f70b4 /arch/x86/kernel | |
parent | fdf5563a720004199324371c08071b8ea27bd994 (diff) | |
parent | 16171bffc829272d5e6014bad48f680cb50943d9 (diff) |
Merge branch 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fpu updates from Ingo Molnar:
"Misc changes:
- add a pkey sanity check
- three commits to improve and future-proof xstate/xfeature handling
some more"
* 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/pkeys: Add check for pkey "overflow"
x86/fpu/xstate: Warn when checking alignment of disabled xfeatures
x86/fpu/xstate: Fix XSAVES offsets in setup_xstate_comp()
x86/fpu/xstate: Fix last_good_offset in setup_xstate_features()
Diffstat (limited to 'arch/x86/kernel')
-rw-r--r-- | arch/x86/kernel/fpu/xstate.c | 75 |
1 files changed, 39 insertions, 36 deletions
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index a1806598aaa4..32b153d38748 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -120,11 +120,6 @@ static bool xfeature_is_supervisor(int xfeature_nr) return ecx & 1; } -static bool xfeature_is_user(int xfeature_nr) -{ - return !xfeature_is_supervisor(xfeature_nr); -} - /* * When executing XSAVEOPT (or other optimized XSAVE instructions), if * a processor implementation detects that an FPU state component is still @@ -265,21 +260,25 @@ static void __init setup_xstate_features(void) cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx); + xstate_sizes[i] = eax; + /* - * If an xfeature is supervisor state, the offset - * in EBX is invalid. We leave it to -1. + * If an xfeature is supervisor state, the offset in EBX is + * invalid, leave it to -1. */ - if (xfeature_is_user(i)) - xstate_offsets[i] = ebx; + if (xfeature_is_supervisor(i)) + continue; + + xstate_offsets[i] = ebx; - xstate_sizes[i] = eax; /* - * In our xstate size checks, we assume that the - * highest-numbered xstate feature has the - * highest offset in the buffer. Ensure it does. + * In our xstate size checks, we assume that the highest-numbered + * xstate feature has the highest offset in the buffer. Ensure + * it does. */ WARN_ONCE(last_good_offset > xstate_offsets[i], - "x86/fpu: misordered xstate at %d\n", last_good_offset); + "x86/fpu: misordered xstate at %d\n", last_good_offset); + last_good_offset = xstate_offsets[i]; } } @@ -326,6 +325,13 @@ static int xfeature_is_aligned(int xfeature_nr) u32 eax, ebx, ecx, edx; CHECK_XFEATURE(xfeature_nr); + + if (!xfeature_enabled(xfeature_nr)) { + WARN_ONCE(1, "Checking alignment of disabled xfeature %d\n", + xfeature_nr); + return 0; + } + cpuid_count(XSTATE_CPUID, xfeature_nr, &eax, &ebx, &ecx, &edx); /* * The value returned by ECX[1] indicates the alignment @@ -338,11 +344,11 @@ static int xfeature_is_aligned(int xfeature_nr) /* * This function sets up offsets and sizes of all extended states in * xsave area. This supports both standard format and compacted format - * of the xsave aread. + * of the xsave area. */ -static void __init setup_xstate_comp(void) +static void __init setup_xstate_comp_offsets(void) { - unsigned int xstate_comp_sizes[XFEATURE_MAX]; + unsigned int next_offset; int i; /* @@ -356,31 +362,23 @@ static void __init setup_xstate_comp(void) if (!boot_cpu_has(X86_FEATURE_XSAVES)) { for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) { - if (xfeature_enabled(i)) { + if (xfeature_enabled(i)) xstate_comp_offsets[i] = xstate_offsets[i]; - xstate_comp_sizes[i] = xstate_sizes[i]; - } } return; } - xstate_comp_offsets[FIRST_EXTENDED_XFEATURE] = - FXSAVE_SIZE + XSAVE_HDR_SIZE; + next_offset = FXSAVE_SIZE + XSAVE_HDR_SIZE; for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) { - if (xfeature_enabled(i)) - xstate_comp_sizes[i] = xstate_sizes[i]; - else - xstate_comp_sizes[i] = 0; + if (!xfeature_enabled(i)) + continue; - if (i > FIRST_EXTENDED_XFEATURE) { - xstate_comp_offsets[i] = xstate_comp_offsets[i-1] - + xstate_comp_sizes[i-1]; + if (xfeature_is_aligned(i)) + next_offset = ALIGN(next_offset, 64); - if (xfeature_is_aligned(i)) - xstate_comp_offsets[i] = - ALIGN(xstate_comp_offsets[i], 64); - } + xstate_comp_offsets[i] = next_offset; + next_offset += xstate_sizes[i]; } } @@ -774,7 +772,7 @@ void __init fpu__init_system_xstate(void) fpu__init_prepare_fx_sw_frame(); setup_init_fpu_buf(); - setup_xstate_comp(); + setup_xstate_comp_offsets(); print_xstate_offset_size(); pr_info("x86/fpu: Enabled xstate features 0x%llx, context size is %d bytes, using '%s' format.\n", @@ -897,8 +895,6 @@ const void *get_xsave_field_ptr(int xfeature_nr) #ifdef CONFIG_ARCH_HAS_PKEYS -#define NR_VALID_PKRU_BITS (CONFIG_NR_PROTECTION_KEYS * 2) -#define PKRU_VALID_MASK (NR_VALID_PKRU_BITS - 1) /* * This will go out and modify PKRU register to set the access * rights for @pkey to @init_val. @@ -917,6 +913,13 @@ int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, if (!boot_cpu_has(X86_FEATURE_OSPKE)) return -EINVAL; + /* + * This code should only be called with valid 'pkey' + * values originating from in-kernel users. Complain + * if a bad value is observed. + */ + WARN_ON_ONCE(pkey >= arch_max_pkey()); + /* Set the bits we need in PKRU: */ if (init_val & PKEY_DISABLE_ACCESS) new_pkru_bits |= PKRU_AD_BIT; |