pm24.git/arch/x86, branch master

Merge tag 'perf_urgent_for_v6.13_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2024-12-09T18:31:35Z

Pull x86 perf fixes from Borislav Petkov: - Make sure the PEBS buffer is drained before reconfiguring the hardware - Add Arrow Lake U support * tag 'perf_urgent_for_v6.13_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/x86/intel/ds: Unconditionally drain PEBS DS when changing PEBS_DATA_CFG perf/x86/intel: Add Arrow Lake U support

x86: Fix build regression with CONFIG_KEXEC_JUMP enabled

2024-12-09T18:13:28Z

Build 6.13-rc12 for x86_64 with gcc 14.2.1 fails with the error: ld: vmlinux.o: in function `virtual_mapped': linux/arch/x86/kernel/relocate_kernel_64.S:249:(.text+0x5915b): undefined reference to `saved_context_gdt_desc' when CONFIG_KEXEC_JUMP is enabled. This was introduced by commit 07fa619f2a40 ("x86/kexec: Restore GDT on return from ::preserve_context kexec") which introduced a use of saved_context_gdt_desc without a declaration for it. Fix that by including asm/asm-offsets.h where saved_context_gdt_desc is defined (indirectly in include/generated/asm-offsets.h which asm/asm-offsets.h includes). Fixes: 07fa619f2a40 ("x86/kexec: Restore GDT on return from ::preserve_context kexec") Signed-off-by: Damien Le Moal Acked-by: Borislav Petkov (AMD) Acked-by: David Woodhouse Closes: https://lore.kernel.org/oe-kbuild-all/202411270006.ZyyzpYf8-lkp@intel.com/ Signed-off-by: Linus Torvalds

Merge tag 'x86_urgent_for_v6.13_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2024-12-08T19:38:56Z

Pull x86 fixes from Borislav Petkov: - Have the Automatic IBRS setting check on AMD does not falsely fire in the guest when it has been set already on the host - Make sure cacheinfo structures memory is allocated to address a boot NULL ptr dereference on Intel Meteor Lake which has different numbers of subleafs in its CPUID(4) leaf - Take care of the GDT restoring on the kexec path too, as expected by the kernel - Make sure SMP is not disabled when IO-APIC is disabled on the kernel cmdline - Add a PGD flag _PAGE_NOPTISHADOW to instruct machinery not to propagate changes to the kernelmode page tables, to the user portion, in PTI - Mark Intel Lunar Lake as affected by an issue where MONITOR wakeups can get lost and thus user-visible delays happen - Make sure PKRU is properly restored with XRSTOR on AMD after a PRKU write of 0 (WRPKRU) which will mark PKRU in its init state and thus lose the actual buffer * tag 'x86_urgent_for_v6.13_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/CPU/AMD: WARN when setting EFER.AUTOIBRS if and only if the WRMSR fails x86/cacheinfo: Delete global num_cache_leaves cacheinfo: Allocate memory during CPU hotplug if not done from the primary CPU x86/kexec: Restore GDT on return from ::preserve_context kexec x86/cpu/topology: Remove limit of CPUs due to disabled IO/APIC x86/mm: Add _PAGE_NOPTISHADOW bit to avoid updating userspace page tables x86/cpu: Add Lunar Lake to list of CPUs with a broken MONITOR implementation x86/pkeys: Ensure updated PKRU value is XRSTOR'd x86/pkeys: Change caller of update_pkru_in_sigframe()

x86/CPU/AMD: WARN when setting EFER.AUTOIBRS if and only if the WRMSR fails

2024-12-06T18:57:05Z

When ensuring EFER.AUTOIBRS is set, WARN only on a negative return code from msr_set_bit(), as '1' is used to indicate the WRMSR was successful ('0' indicates the MSR bit was already set). Fixes: 8cc68c9c9e92 ("x86/CPU/AMD: Make sure EFER[AIBRSE] is set") Reported-by: Nathan Chancellor Signed-off-by: Sean Christopherson Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/Z1MkNofJjt7Oq0G6@google.com Closes: https://lore.kernel.org/all/20241205220604.GA2054199@thelio-3990X

x86/cacheinfo: Delete global num_cache_leaves

2024-12-06T12:13:36Z

Linux remembers cpu_cachinfo::num_leaves per CPU, but x86 initializes all CPUs from the same global "num_cache_leaves". This is erroneous on systems such as Meteor Lake, where each CPU has a distinct num_leaves value. Delete the global "num_cache_leaves" and initialize num_leaves on each CPU. init_cache_level() no longer needs to set num_leaves. Also, it never had to set num_levels as it is unnecessary in x86. Keep checking for zero cache leaves. Such condition indicates a bug. [ bp: Cleanup. ] Signed-off-by: Ricardo Neri Signed-off-by: Borislav Petkov (AMD) Cc: stable@vger.kernel.org # 6.3+ Link: https://lore.kernel.org/r/20241128002247.26726-3-ricardo.neri-calderon@linux.intel.com

x86/kexec: Restore GDT on return from ::preserve_context kexec

2024-12-06T09:35:49Z

The restore_processor_state() function explicitly states that "the asm code that gets us here will have restored a usable GDT". That wasn't true in the case of returning from a ::preserve_context kexec. Make it so. Without this, the kernel was depending on the called function to reload a GDT which is appropriate for the kernel before returning. Test program: #include #include #include #include #include #include #include #include int main (void) { struct kexec_segment segment = {}; unsigned char purgatory[] = { 0x66, 0xba, 0xf8, 0x03, // mov $0x3f8, %dx 0xb0, 0x42, // mov $0x42, %al 0xee, // outb %al, (%dx) 0xc3, // ret }; int ret; segment.buf = &purgatory; segment.bufsz = sizeof(purgatory); segment.mem = (void *)0x400000; segment.memsz = 0x1000; ret = syscall(__NR_kexec_load, 0x400000, 1, &segment, KEXEC_PRESERVE_CONTEXT); if (ret) { perror("kexec_load"); exit(1); } ret = syscall(__NR_reboot, LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2, LINUX_REBOOT_CMD_KEXEC); if (ret) { perror("kexec reboot"); exit(1); } printf("Success\n"); return 0; } Signed-off-by: David Woodhouse Signed-off-by: Ingo Molnar Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20241205153343.3275139-2-dwmw2@infradead.org

x86/cpu/topology: Remove limit of CPUs due to disabled IO/APIC

2024-12-05T13:43:32Z

The rework of possible CPUs management erroneously disabled SMP when the IO/APIC is disabled either by the 'noapic' command line parameter or during IO/APIC setup. SMP is possible without IO/APIC. Remove the ioapic_is_disabled conditions from the relevant possible CPU management code paths to restore the orgininal behaviour. Fixes: 7c0edad3643f ("x86/cpu/topology: Rework possible CPU management") Signed-off-by: Fernando Fernandez Mancera Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/20241202145905.1482-1-ffmancera@riseup.net

x86/mm: Add _PAGE_NOPTISHADOW bit to avoid updating userspace page tables

2024-12-05T12:04:00Z

The set_p4d() and set_pgd() functions (in 4-level or 5-level page table setups respectively) assume that the root page table is actually a 8KiB allocation, with the userspace root immediately after the kernel root page table (so that the former can enforce NX on on all the subordinate page tables, which are actually shared). However, users of the kernel_ident_mapping_init() code do not give it an 8KiB allocation for its PGD. Both swsusp_arch_resume() and acpi_mp_setup_reset() allocate only a single 4KiB page. The kexec code on x86_64 currently gets away with it purely by chance, because it allocates 8KiB for its "control code page" and then actually uses the first half for the PGD, then copies the actual trampoline code into the second half only after the identmap code has finished scribbling over it. Fix this by defining a _PAGE_NOPTISHADOW bit (which can use the same bit as _PAGE_SAVED_DIRTY since one is only for the PGD/P4D root and the other is exclusively for leaf PTEs.). This instructs __pti_set_user_pgtbl() not to write to the userspace 'shadow' PGD. Strictly, the _PAGE_NOPTISHADOW bit doesn't need to be written out to the actual page tables; since __pti_set_user_pgtbl() returns the value to be written to the kernel page table, it could be filtered out. But there seems to be no benefit to actually doing so. Suggested-by: Dave Hansen Signed-off-by: David Woodhouse Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/412c90a4df7aef077141d9f68d19cbe5602d6c6d.camel@infradead.org Cc: stable@kernel.org Cc: Linus Torvalds Cc: Andy Lutomirski Cc: Peter Zijlstra Cc: Rik van Riel

x86/cpu: Add Lunar Lake to list of CPUs with a broken MONITOR implementation

2024-12-04T20:30:14Z

Under some conditions, MONITOR wakeups on Lunar Lake processors can be lost, resulting in significant user-visible delays. Add Lunar Lake to X86_BUG_MONITOR so that wake_up_idle_cpu() always sends an IPI, avoiding this potential delay. Reported originally here: https://bugzilla.kernel.org/show_bug.cgi?id=219364 [ dhansen: tweak subject ] Signed-off-by: Len Brown Signed-off-by: Dave Hansen Reviewed-by: Rafael J. Wysocki Cc:stable@vger.kernel.org Link: https://lore.kernel.org/all/a4aa8842a3c3bfdb7fe9807710eef159cbf0e705.1731463305.git.len.brown%40intel.com

x86/pkeys: Ensure updated PKRU value is XRSTOR'd

2024-12-02T23:25:29Z

When XSTATE_BV[i] is 0, and XRSTOR attempts to restore state component 'i' it ignores any value in the XSAVE buffer and instead restores the state component's init value. This means that if XSAVE writes XSTATE_BV[PKRU]=0 then XRSTOR will ignore the value that update_pkru_in_sigframe() writes to the XSAVE buffer. XSTATE_BV[PKRU] only gets written as 0 if PKRU is in its init state. On Intel CPUs, basically never happens because the kernel usually overwrites the init value (aside: this is why we didn't notice this bug until now). But on AMD, the init tracker is more aggressive and will track PKRU as being in its init state upon any wrpkru(0x0). Unfortunately, sig_prepare_pkru() does just that: wrpkru(0x0). This writes XSTATE_BV[PKRU]=0 which makes XRSTOR ignore the PKRU value in the sigframe. To fix this, always overwrite the sigframe XSTATE_BV with a value that has XSTATE_BV[PKRU]==1. This ensures that XRSTOR will not ignore what update_pkru_in_sigframe() wrote. The problematic sequence of events is something like this: Userspace does: * wrpkru(0xffff0000) (or whatever) * Hardware sets: XINUSE[PKRU]=1 Signal happens, kernel is entered: * sig_prepare_pkru() => wrpkru(0x00000000) * Hardware sets: XINUSE[PKRU]=0 (aggressive AMD init tracker) * XSAVE writes most of XSAVE buffer, including XSTATE_BV[PKRU]=XINUSE[PKRU]=0 * update_pkru_in_sigframe() overwrites PKRU in XSAVE buffer ... signal handling * XRSTOR sees XSTATE_BV[PKRU]==0, ignores just-written value from update_pkru_in_sigframe() Fixes: 70044df250d0 ("x86/pkeys: Update PKRU to enable all pkeys before XSAVE") Suggested-by: Rudi Horn Signed-off-by: Aruna Ramakrishna Signed-off-by: Dave Hansen Acked-by: Dave Hansen Link: https://lore.kernel.org/all/20241119174520.3987538-3-aruna.ramakrishna%40oracle.com