Merge tag 'x86-mm-2023-10-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 mm handling updates from Ingo Molnar:

 - Add new NX-stack self-test

 - Improve NUMA partial-CFMWS handling

 - Fix #VC handler bugs resulting in SEV-SNP boot failures

 - Drop the 4MB memory size restriction on minimal NUMA nodes

 - Reorganize headers a bit, in preparation to header dependency
   reduction efforts

 - Misc cleanups & fixes

* tag 'x86-mm-2023-10-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm: Drop the 4 MB restriction on minimal NUMA node memory size
  selftests/x86/lam: Zero out buffer for readlink()
  x86/sev: Drop unneeded #include
  x86/sev: Move sev_setup_arch() to mem_encrypt.c
  x86/tdx: Replace deprecated strncpy() with strtomem_pad()
  selftests/x86/mm: Add new test that userspace stack is in fact NX
  x86/sev: Make boot_ghcb_page[] static
  x86/boot: Move x86_cache_alignment initialization to correct spot
  x86/sev-es: Set x86_virt_bits to the correct value straight away, instead of a two-phase approach
  x86/sev-es: Allow copy_from_kernel_nofault() in earlier boot
  x86_64: Show CR4.PSE on auxiliaries like on BSP
  x86/iommu/docs: Update AMD IOMMU specification document URL
  x86/sev/docs: Update document URL in amd-memory-encryption.rst
  x86/mm: Move arch_memory_failure() and arch_is_platform_page() definitions from <asm/processor.h> to <asm/pgtable.h>
  ACPI/NUMA: Apply SRAT proximity domain to entire CFMWS window
  x86/numa: Introduce numa_fill_memblks()

3 files changed, 219 insertions, 3 deletions

diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile
index 7e8c937627dd..0b872c0a42d2 100644
--- a/tools/testing/selftests/x86/Makefile
+++ b/tools/testing/selftests/x86/Makefile
@@ -14,6 +14,7 @@ TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs syscall_nt test_mremap
 			check_initial_reg_state sigreturn iopl ioperm \
 			test_vsyscall mov_ss_trap \
 			syscall_arg_fault fsgsbase_restore sigaltstack
+TARGETS_C_BOTHBITS += nx_stack
 TARGETS_C_32BIT_ONLY := entry_from_vm86 test_syscall_vdso unwind_vdso \
 			test_FCMOV test_FCOMI test_FISTTP \
 			vdso_restorer
@@ -109,3 +110,6 @@ $(OUTPUT)/test_syscall_vdso_32: thunks_32.S
 # state.
 $(OUTPUT)/check_initial_reg_state_32: CFLAGS += -Wl,-ereal_start -static
 $(OUTPUT)/check_initial_reg_state_64: CFLAGS += -Wl,-ereal_start -static
+
+$(OUTPUT)/nx_stack_32: CFLAGS += -Wl,-z,noexecstack
+$(OUTPUT)/nx_stack_64: CFLAGS += -Wl,-z,noexecstack
diff --git a/tools/testing/selftests/x86/lam.c b/tools/testing/selftests/x86/lam.c
index eb0e46905bf9..8f9b06d9ce03 100644
--- a/tools/testing/selftests/x86/lam.c
+++ b/tools/testing/selftests/x86/lam.c
@@ -573,7 +573,7 @@ int do_uring(unsigned long lam)
 	char path[PATH_MAX] = {0};
 
 	/* get current process path */
-	if (readlink("/proc/self/exe", path, PATH_MAX) <= 0)
+	if (readlink("/proc/self/exe", path, PATH_MAX - 1) <= 0)
 		return 1;
 
 	int file_fd = open(path, O_RDONLY);
@@ -680,14 +680,14 @@ static int handle_execve(struct testcases *test)
 		perror("Fork failed.");
 		ret = 1;
 	} else if (pid == 0) {
-		char path[PATH_MAX];
+		char path[PATH_MAX] = {0};
 
 		/* Set LAM mode in parent process */
 		if (set_lam(lam) != 0)
 			return 1;
 
 		/* Get current binary's path and the binary was run by execve */
-		if (readlink("/proc/self/exe", path, PATH_MAX) <= 0)
+		if (readlink("/proc/self/exe", path, PATH_MAX - 1) <= 0)
 			exit(-1);
 
 		/* run binary to get LAM mode and return to parent process */
diff --git a/tools/testing/selftests/x86/nx_stack.c b/tools/testing/selftests/x86/nx_stack.c
new file mode 100644
index 000000000000..ea4a4e246879
--- /dev/null
+++ b/tools/testing/selftests/x86/nx_stack.c
@@ -0,0 +1,212 @@
+/*
+ * Copyright (c) 2023 Alexey Dobriyan <adobriyan@gmail.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+/*
+ * Test that userspace stack is NX. Requires linking with -Wl,-z,noexecstack
+ * because I don't want to bother with PT_GNU_STACK detection.
+ *
+ * Fill the stack with INT3's and then try to execute some of them:
+ * SIGSEGV -- good, SIGTRAP -- bad.
+ *
+ * Regular stack is completely overwritten before testing.
+ * Test doesn't exit SIGSEGV handler after first fault at INT3.
+ */
+#undef _GNU_SOURCE
+#define _GNU_SOURCE
+#undef NDEBUG
+#include <assert.h>
+#include <signal.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/mman.h>
+#include <sys/resource.h>
+#include <unistd.h>
+
+#define PAGE_SIZE 4096
+
+/*
+ * This is memset(rsp, 0xcc, -1); but down.
+ * It will SIGSEGV when bottom of the stack is reached.
+ * Byte-size access is important! (see rdi tweak in the signal handler).
+ */
+void make_stack1(void);
+asm(
+".pushsection .text\n"
+".globl make_stack1\n"
+".align 16\n"
+"make_stack1:\n"
+	"mov $0xcc, %al\n"
+#if defined __amd64__
+	"mov %rsp, %rdi\n"
+	"mov $-1, %rcx\n"
+#elif defined __i386__
+	"mov %esp, %edi\n"
+	"mov $-1, %ecx\n"
+#else
+#error
+#endif
+	"std\n"
+	"rep stosb\n"
+	/* unreachable */
+	"hlt\n"
+".type make_stack1,@function\n"
+".size make_stack1,.-make_stack1\n"
+".popsection\n"
+);
+
+/*
+ * memset(p, 0xcc, -1);
+ * It will SIGSEGV when top of the stack is reached.
+ */
+void make_stack2(uint64_t p);
+asm(
+".pushsection .text\n"
+".globl make_stack2\n"
+".align 16\n"
+"make_stack2:\n"
+	"mov $0xcc, %al\n"
+#if defined __amd64__
+	"mov $-1, %rcx\n"
+#elif defined __i386__
+	"mov $-1, %ecx\n"
+#else
+#error
+#endif
+	"cld\n"
+	"rep stosb\n"
+	/* unreachable */
+	"hlt\n"
+".type make_stack2,@function\n"
+".size make_stack2,.-make_stack2\n"
+".popsection\n"
+);
+
+static volatile int test_state = 0;
+static volatile unsigned long stack_min_addr;
+
+#if defined __amd64__
+#define RDI	REG_RDI
+#define RIP	REG_RIP
+#define RIP_STRING "rip"
+#elif defined __i386__
+#define RDI	REG_EDI
+#define RIP	REG_EIP
+#define RIP_STRING "eip"
+#else
+#error
+#endif
+
+static void sigsegv(int _, siginfo_t *__, void *uc_)
+{
+	/*
+	 * Some Linux versions didn't clear DF before entering signal
+	 * handler. make_stack1() doesn't have a chance to clear DF
+	 * either so we clear it by hand here.
+	 */
+	asm volatile ("cld" ::: "memory");
+
+	ucontext_t *uc = uc_;
+
+	if (test_state == 0) {
+		/* Stack is faulted and cleared from RSP to the lowest address. */
+		stack_min_addr = ++uc->uc_mcontext.gregs[RDI];
+		if (1) {
+			printf("stack min %lx\n", stack_min_addr);
+		}
+		uc->uc_mcontext.gregs[RIP] = (uintptr_t)&make_stack2;
+		test_state = 1;
+	} else if (test_state == 1) {
+		/* Stack has been cleared from top to bottom. */
+		unsigned long stack_max_addr = uc->uc_mcontext.gregs[RDI];
+		if (1) {
+			printf("stack max %lx\n", stack_max_addr);
+		}
+		/* Start faulting pages on stack and see what happens. */
+		uc->uc_mcontext.gregs[RIP] = stack_max_addr - PAGE_SIZE;
+		test_state = 2;
+	} else if (test_state == 2) {
+		/* Stack page is NX -- good, test next page. */
+		uc->uc_mcontext.gregs[RIP] -= PAGE_SIZE;
+		if (uc->uc_mcontext.gregs[RIP] == stack_min_addr) {
+			/* One more SIGSEGV and test ends. */
+			test_state = 3;
+		}
+	} else {
+		printf("PASS\tAll stack pages are NX\n");
+		_exit(EXIT_SUCCESS);
+	}
+}
+
+static void sigtrap(int _, siginfo_t *__, void *uc_)
+{
+	const ucontext_t *uc = uc_;
+	unsigned long rip = uc->uc_mcontext.gregs[RIP];
+	printf("FAIL\texecutable page on the stack: " RIP_STRING " %lx\n", rip);
+	_exit(EXIT_FAILURE);
+}
+
+int main(void)
+{
+	{
+		struct sigaction act = {};
+		sigemptyset(&act.sa_mask);
+		act.sa_flags = SA_SIGINFO;
+		act.sa_sigaction = &sigsegv;
+		int rv = sigaction(SIGSEGV, &act, NULL);
+		assert(rv == 0);
+	}
+	{
+		struct sigaction act = {};
+		sigemptyset(&act.sa_mask);
+		act.sa_flags = SA_SIGINFO;
+		act.sa_sigaction = &sigtrap;
+		int rv = sigaction(SIGTRAP, &act, NULL);
+		assert(rv == 0);
+	}
+	{
+		struct rlimit rlim;
+		int rv = getrlimit(RLIMIT_STACK, &rlim);
+		assert(rv == 0);
+		/* Cap stack at time-honored 8 MiB value. */
+		rlim.rlim_max = rlim.rlim_cur;
+		if (rlim.rlim_max > 8 * 1024 * 1024) {
+			rlim.rlim_max = 8 * 1024 * 1024;
+		}
+		rv = setrlimit(RLIMIT_STACK, &rlim);
+		assert(rv == 0);
+	}
+	{
+		/*
+		 * We don't know now much stack SIGSEGV handler uses.
+		 * Bump this by 1 page every time someone complains,
+		 * or rewrite it in assembly.
+		 */
+		const size_t len = SIGSTKSZ;
+		void *p = mmap(NULL, len, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
+		assert(p != MAP_FAILED);
+		stack_t ss = {};
+		ss.ss_sp = p;
+		ss.ss_size = len;
+		int rv = sigaltstack(&ss, NULL);
+		assert(rv == 0);
+	}
+	make_stack1();
+	/*
+	 * Unreachable, but if _this_ INT3 is ever reached, it's a bug somewhere.
+	 * Fold it into main SIGTRAP pathway.
+	 */
+	__builtin_trap();
+}