Merge tag 'x86-core-2025-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull core x86 updates from Ingo Molnar:
 "x86 CPU features support:
   - Generate the <asm/cpufeaturemasks.h> header based on build config
     (H. Peter Anvin, Xin Li)
   - x86 CPUID parsing updates and fixes (Ahmed S. Darwish)
   - Introduce the 'setcpuid=' boot parameter (Brendan Jackman)
   - Enable modifying CPU bug flags with '{clear,set}puid=' (Brendan
     Jackman)
   - Utilize CPU-type for CPU matching (Pawan Gupta)
   - Warn about unmet CPU feature dependencies (Sohil Mehta)
   - Prepare for new Intel Family numbers (Sohil Mehta)

  Percpu code:
   - Standardize & reorganize the x86 percpu layout and related cleanups
     (Brian Gerst)
   - Convert the stackprotector canary to a regular percpu variable
     (Brian Gerst)
   - Add a percpu subsection for cache hot data (Brian Gerst)
   - Unify __pcpu_op{1,2}_N() macros to __pcpu_op_N() (Uros Bizjak)
   - Construct __percpu_seg_override from __percpu_seg (Uros Bizjak)

  MM:
   - Add support for broadcast TLB invalidation using AMD's INVLPGB
     instruction (Rik van Riel)
   - Rework ROX cache to avoid writable copy (Mike Rapoport)
   - PAT: restore large ROX pages after fragmentation (Kirill A.
     Shutemov, Mike Rapoport)
   - Make memremap(MEMREMAP_WB) map memory as encrypted by default
     (Kirill A. Shutemov)
   - Robustify page table initialization (Kirill A. Shutemov)
   - Fix flush_tlb_range() when used for zapping normal PMDs (Jann Horn)
   - Clear _PAGE_DIRTY for kernel mappings when we clear _PAGE_RW
     (Matthew Wilcox)

  KASLR:
   - x86/kaslr: Reduce KASLR entropy on most x86 systems, to support PCI
     BAR space beyond the 10TiB region (CONFIG_PCI_P2PDMA=y) (Balbir
     Singh)

  CPU bugs:
   - Implement FineIBT-BHI mitigation (Peter Zijlstra)
   - speculation: Simplify and make CALL_NOSPEC consistent (Pawan Gupta)
   - speculation: Add a conditional CS prefix to CALL_NOSPEC (Pawan
     Gupta)
   - RFDS: Exclude P-only parts from the RFDS affected list (Pawan
     Gupta)

  System calls:
   - Break up entry/common.c (Brian Gerst)
   - Move sysctls into arch/x86 (Joel Granados)

  Intel LAM support updates: (Maciej Wieczor-Retman)
   - selftests/lam: Move cpu_has_la57() to use cpuinfo flag
   - selftests/lam: Skip test if LAM is disabled
   - selftests/lam: Test get_user() LAM pointer handling

  AMD SMN access updates:
   - Add SMN offsets to exclusive region access (Mario Limonciello)
   - Add support for debugfs access to SMN registers (Mario Limonciello)
   - Have HSMP use SMN through AMD_NODE (Yazen Ghannam)

  Power management updates: (Patryk Wlazlyn)
   - Allow calling mwait_play_dead with an arbitrary hint
   - ACPI/processor_idle: Add FFH state handling
   - intel_idle: Provide the default enter_dead() handler
   - Eliminate mwait_play_dead_cpuid_hint()

  Build system:
   - Raise the minimum GCC version to 8.1 (Brian Gerst)
   - Raise the minimum LLVM version to 15.0.0 (Nathan Chancellor)

  Kconfig: (Arnd Bergmann)
   - Add cmpxchg8b support back to Geode CPUs
   - Drop 32-bit "bigsmp" machine support
   - Rework CONFIG_GENERIC_CPU compiler flags
   - Drop configuration options for early 64-bit CPUs
   - Remove CONFIG_HIGHMEM64G support
   - Drop CONFIG_SWIOTLB for PAE
   - Drop support for CONFIG_HIGHPTE
   - Document CONFIG_X86_INTEL_MID as 64-bit-only
   - Remove old STA2x11 support
   - Only allow CONFIG_EISA for 32-bit

  Headers:
   - Replace __ASSEMBLY__ with __ASSEMBLER__ in UAPI and non-UAPI
     headers (Thomas Huth)

  Assembly code & machine code patching:
   - x86/alternatives: Simplify alternative_call() interface (Josh
     Poimboeuf)
   - x86/alternatives: Simplify callthunk patching (Peter Zijlstra)
   - KVM: VMX: Use named operands in inline asm (Josh Poimboeuf)
   - x86/hyperv: Use named operands in inline asm (Josh Poimboeuf)
   - x86/traps: Cleanup and robustify decode_bug() (Peter Zijlstra)
   - x86/kexec: Merge x86_32 and x86_64 code using macros from
     <asm/asm.h> (Uros Bizjak)
   - Use named operands in inline asm (Uros Bizjak)
   - Improve performance by using asm_inline() for atomic locking
     instructions (Uros Bizjak)

  Earlyprintk:
   - Harden early_serial (Peter Zijlstra)

  NMI handler:
   - Add an emergency handler in nmi_desc & use it in
     nmi_shootdown_cpus() (Waiman Long)

  Miscellaneous fixes and cleanups:
   - by Ahmed S. Darwish, Andy Shevchenko, Ard Biesheuvel, Artem
     Bityutskiy, Borislav Petkov, Brendan Jackman, Brian Gerst, Dan
     Carpenter, Dr. David Alan Gilbert, H. Peter Anvin, Ingo Molnar,
     Josh Poimboeuf, Kevin Brodsky, Mike Rapoport, Lukas Bulwahn, Maciej
     Wieczor-Retman, Max Grobecker, Patryk Wlazlyn, Pawan Gupta, Peter
     Zijlstra, Philip Redkin, Qasim Ijaz, Rik van Riel, Thomas Gleixner,
     Thorsten Blum, Tom Lendacky, Tony Luck, Uros Bizjak, Vitaly
     Kuznetsov, Xin Li, liuye"

* tag 'x86-core-2025-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (211 commits)
  zstd: Increase DYNAMIC_BMI2 GCC version cutoff from 4.8 to 11.0 to work around compiler segfault
  x86/asm: Make asm export of __ref_stack_chk_guard unconditional
  x86/mm: Only do broadcast flush from reclaim if pages were unmapped
  perf/x86/intel, x86/cpu: Replace Pentium 4 model checks with VFM ones
  perf/x86/intel, x86/cpu: Simplify Intel PMU initialization
  x86/headers: Replace __ASSEMBLY__ with __ASSEMBLER__ in non-UAPI headers
  x86/headers: Replace __ASSEMBLY__ with __ASSEMBLER__ in UAPI headers
  x86/locking/atomic: Improve performance by using asm_inline() for atomic locking instructions
  x86/asm: Use asm_inline() instead of asm() in clwb()
  x86/asm: Use CLFLUSHOPT and CLWB mnemonics in <asm/special_insns.h>
  x86/hweight: Use asm_inline() instead of asm()
  x86/hweight: Use ASM_CALL_CONSTRAINT in inline asm()
  x86/hweight: Use named operands in inline asm()
  x86/stackprotector/64: Only export __ref_stack_chk_guard on CONFIG_SMP
  x86/head/64: Avoid Clang < 17 stack protector in startup code
  x86/kexec: Merge x86_32 and x86_64 code using macros from <asm/asm.h>
  x86/runtime-const: Add the RUNTIME_CONST_PTR assembly macro
  x86/cpu/intel: Limit the non-architectural constant_tsc model checks
  x86/mm/pat: Replace Intel x86_model checks with VFM ones
  x86/cpu/intel: Fix fast string initialization for extended Families
  ...

1 files changed, 108 insertions, 3 deletions

diff --git a/arch/x86/entry/syscall_64.c b/arch/x86/entry/syscall_64.c
index ba8354424860..b6e68ea98b83 100644
--- a/arch/x86/entry/syscall_64.c
+++ b/arch/x86/entry/syscall_64.c
@@ -1,15 +1,20 @@
-// SPDX-License-Identifier: GPL-2.0
-/* System call table for x86-64. */
+// SPDX-License-Identifier: GPL-2.0-only
+/* 64-bit system call dispatch */
 
 #include <linux/linkage.h>
 #include <linux/sys.h>
 #include <linux/cache.h>
 #include <linux/syscalls.h>
+#include <linux/entry-common.h>
+#include <linux/nospec.h>
 #include <asm/syscall.h>
 
 #define __SYSCALL(nr, sym) extern long __x64_##sym(const struct pt_regs *);
 #define __SYSCALL_NORETURN(nr, sym) extern long __noreturn __x64_##sym(const struct pt_regs *);
 #include <asm/syscalls_64.h>
+#ifdef CONFIG_X86_X32_ABI
+#include <asm/syscalls_x32.h>
+#endif
 #undef  __SYSCALL
 
 #undef  __SYSCALL_NORETURN
@@ -33,4 +38,104 @@ long x64_sys_call(const struct pt_regs *regs, unsigned int nr)
 	#include <asm/syscalls_64.h>
 	default: return __x64_sys_ni_syscall(regs);
 	}
-};
+}
+
+#ifdef CONFIG_X86_X32_ABI
+long x32_sys_call(const struct pt_regs *regs, unsigned int nr)
+{
+	switch (nr) {
+	#include <asm/syscalls_x32.h>
+	default: return __x64_sys_ni_syscall(regs);
+	}
+}
+#endif
+
+static __always_inline bool do_syscall_x64(struct pt_regs *regs, int nr)
+{
+	/*
+	 * Convert negative numbers to very high and thus out of range
+	 * numbers for comparisons.
+	 */
+	unsigned int unr = nr;
+
+	if (likely(unr < NR_syscalls)) {
+		unr = array_index_nospec(unr, NR_syscalls);
+		regs->ax = x64_sys_call(regs, unr);
+		return true;
+	}
+	return false;
+}
+
+static __always_inline bool do_syscall_x32(struct pt_regs *regs, int nr)
+{
+	/*
+	 * Adjust the starting offset of the table, and convert numbers
+	 * < __X32_SYSCALL_BIT to very high and thus out of range
+	 * numbers for comparisons.
+	 */
+	unsigned int xnr = nr - __X32_SYSCALL_BIT;
+
+	if (IS_ENABLED(CONFIG_X86_X32_ABI) && likely(xnr < X32_NR_syscalls)) {
+		xnr = array_index_nospec(xnr, X32_NR_syscalls);
+		regs->ax = x32_sys_call(regs, xnr);
+		return true;
+	}
+	return false;
+}
+
+/* Returns true to return using SYSRET, or false to use IRET */
+__visible noinstr bool do_syscall_64(struct pt_regs *regs, int nr)
+{
+	add_random_kstack_offset();
+	nr = syscall_enter_from_user_mode(regs, nr);
+
+	instrumentation_begin();
+
+	if (!do_syscall_x64(regs, nr) && !do_syscall_x32(regs, nr) && nr != -1) {
+		/* Invalid system call, but still a system call. */
+		regs->ax = __x64_sys_ni_syscall(regs);
+	}
+
+	instrumentation_end();
+	syscall_exit_to_user_mode(regs);
+
+	/*
+	 * Check that the register state is valid for using SYSRET to exit
+	 * to userspace.  Otherwise use the slower but fully capable IRET
+	 * exit path.
+	 */
+
+	/* XEN PV guests always use the IRET path */
+	if (cpu_feature_enabled(X86_FEATURE_XENPV))
+		return false;
+
+	/* SYSRET requires RCX == RIP and R11 == EFLAGS */
+	if (unlikely(regs->cx != regs->ip || regs->r11 != regs->flags))
+		return false;
+
+	/* CS and SS must match the values set in MSR_STAR */
+	if (unlikely(regs->cs != __USER_CS || regs->ss != __USER_DS))
+		return false;
+
+	/*
+	 * On Intel CPUs, SYSRET with non-canonical RCX/RIP will #GP
+	 * in kernel space.  This essentially lets the user take over
+	 * the kernel, since userspace controls RSP.
+	 *
+	 * TASK_SIZE_MAX covers all user-accessible addresses other than
+	 * the deprecated vsyscall page.
+	 */
+	if (unlikely(regs->ip >= TASK_SIZE_MAX))
+		return false;
+
+	/*
+	 * SYSRET cannot restore RF.  It can restore TF, but unlike IRET,
+	 * restoring TF results in a trap from userspace immediately after
+	 * SYSRET.
+	 */
+	if (unlikely(regs->flags & (X86_EFLAGS_RF | X86_EFLAGS_TF)))
+		return false;
+
+	/* Use SYSRET to exit to userspace */
+	return true;
+}