LoongArch fixes for v7.1-rc5

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Merge tag 'loongarch-fixes-7.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson

Pull LoongArch fixes from Huacai Chen:
 "Rework KASLR to avoid initrd overlap, remove some unused code to avoid
  a build warning, fix some bugs in kprobes and KVM"

* tag 'loongarch-fixes-7.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson:
  LoongArch: KVM: Move some variable declarations to paravirt.h
  LoongArch: kprobes: Fix handling of fatal unrecoverable recursions
  LoongArch: kprobes: Use larch_insn_text_copy() to patch instructions
  LoongArch: Remove unused code to avoid build warning
  LoongArch: Avoid initrd overlap during kernel relocation
  LoongArch: Skip relocation-time KASLR if already applied
  efi/loongarch: Randomize kernel preferred address for KASLR

arch/loongarch/include/asm/efi.h

@@ -30,6 +30,8 @@ static inline unsigned long efi_get_kimg_min_align(void)
 	return SZ_2M;
 }
 
-#define EFI_KIMG_PREFERRED_ADDRESS	PHYSADDR(VMLINUX_LOAD_ADDRESS)
+unsigned long efi_get_kimg_kaslr_address(void);
+
+#define EFI_KIMG_PREFERRED_ADDRESS efi_get_kimg_kaslr_address()
 
 #endif /* _ASM_LOONGARCH_EFI_H */

arch/loongarch/include/asm/paravirt.h

@@ -4,6 +4,12 @@
 
 #ifdef CONFIG_PARAVIRT
 
+#include <linux/jump_label.h>
+
+DECLARE_STATIC_KEY_FALSE(virt_preempt_key);
+DECLARE_STATIC_KEY_FALSE(virt_spin_lock_key);
+DECLARE_PER_CPU(struct kvm_steal_time, steal_time);
+
 int __init pv_ipi_init(void);
 int __init pv_time_init(void);
 int __init pv_spinlock_init(void);

arch/loongarch/include/asm/qspinlock.h

@@ -3,12 +3,9 @@
 #define _ASM_LOONGARCH_QSPINLOCK_H
 
 #include <asm/kvm_para.h>
-#include <linux/jump_label.h>
+#include <asm/paravirt.h>
 
 #ifdef CONFIG_PARAVIRT
-DECLARE_STATIC_KEY_FALSE(virt_preempt_key);
-DECLARE_STATIC_KEY_FALSE(virt_spin_lock_key);
-DECLARE_PER_CPU(struct kvm_steal_time, steal_time);
 
 #define virt_spin_lock virt_spin_lock
 

arch/loongarch/kernel/kprobes.c

@@ -60,16 +60,18 @@ NOKPROBE_SYMBOL(arch_prepare_kprobe);
 /* Install breakpoint in text */
 void arch_arm_kprobe(struct kprobe *p)
 {
-	*p->addr = KPROBE_BP_INSN;
-	flush_insn_slot(p);
+	u32 insn = KPROBE_BP_INSN;
+
+	larch_insn_text_copy(p->addr, &insn, LOONGARCH_INSN_SIZE);
 }
 NOKPROBE_SYMBOL(arch_arm_kprobe);
 
 /* Remove breakpoint from text */
 void arch_disarm_kprobe(struct kprobe *p)
 {
-	*p->addr = p->opcode;
-	flush_insn_slot(p);
+	u32 insn = p->opcode;
+
+	larch_insn_text_copy(p->addr, &insn, LOONGARCH_INSN_SIZE);
 }
 NOKPROBE_SYMBOL(arch_disarm_kprobe);
 
@@ -184,16 +186,16 @@ static bool reenter_kprobe(struct kprobe *p, struct pt_regs *regs,
 			   struct kprobe_ctlblk *kcb)
 {
 	switch (kcb->kprobe_status) {
-	case KPROBE_HIT_SS:
 	case KPROBE_HIT_SSDONE:
 	case KPROBE_HIT_ACTIVE:
 		kprobes_inc_nmissed_count(p);
 		setup_singlestep(p, regs, kcb, 1);
 		break;
+	case KPROBE_HIT_SS:
 	case KPROBE_REENTER:
 		pr_warn("Failed to recover from reentered kprobes.\n");
 		dump_kprobe(p);
-		WARN_ON_ONCE(1);
+		BUG();
 		break;
 	default:
 		WARN_ON(1);

arch/loongarch/kernel/relocate.c

@@ -134,11 +134,23 @@ early_param("nokaslr", nokaslr);
 
 #define KASLR_DISABLED_MESSAGE "KASLR is disabled by %s in %s cmdline.\n"
 
+/*
+ * Note: strictly-defined KASLR means the kernel's final runtime address
+ * has a random offset from the kernel's load address, which is implemented
+ * in relocate.c; broadly-defined KALSR means the kernel's final runtime
+ * address has a random offset from the kernel's link address (a.k.a.
+ * VMLINUX_LOAD_ADDRESS), which also include the efistlub implementation,
+ * kexec_file implementation and QEMU direct kernel boot. kaslr_disabled()
+ * return true only means strictly-defined KASLR is disabled.
+ */
 static inline __init bool kaslr_disabled(void)
 {
 	char *str;
 	const char *builtin_cmdline = CONFIG_CMDLINE;
 
+	if (kaslr_offset())
+		return true; /* KASLR is performed during early boot. */
+
 	str = strstr(builtin_cmdline, "nokaslr");
 	if (str == builtin_cmdline || (str > builtin_cmdline && *(str - 1) == ' ')) {
 		pr_info(KASLR_DISABLED_MESSAGE, "\'nokaslr\'", "built-in");
@@ -210,14 +222,52 @@ static inline void __init *determine_relocation_address(void)
 	return RELOCATED_KASLR(destination);
 }
 
+static unsigned long __init determine_initrd_address(unsigned long *size)
+{
+	unsigned long start = 0;
+	unsigned long key_length;
+	char *p, *endp, *key = "initrd=";
+
+	key_length = strlen(key);
+	p = strstr(boot_command_line, key);
+
+	if (!p) {
+		key = "initrdmem=";
+		key_length = strlen(key);
+		p = strstr(boot_command_line, key);
+	}
+
+	if (p == boot_command_line || (p > boot_command_line && *(p - 1) == ' ')) {
+		p += key_length;
+		start = memparse(p, &endp);
+		if (*endp == ',')
+			*size = memparse(endp + 1, NULL);
+	}
+
+	return start;
+}
+
 static inline int __init relocation_addr_valid(void *location_new)
 {
+	unsigned long kernel_start, kernel_size;
+	unsigned long initrd_start, initrd_size = 0;
+
 	if ((unsigned long)location_new & 0x00000ffff)
 		return 0; /* Inappropriately aligned new location */
 
 	if ((unsigned long)location_new < (unsigned long)_end)
 		return 0; /* New location overlaps original kernel */
 
+	initrd_start = determine_initrd_address(&initrd_size);
+	if (initrd_start && initrd_size) {
+		kernel_start = PHYSADDR(location_new);
+		kernel_size = (unsigned long)_end - (unsigned long)_text;
+
+		if (kernel_start < (initrd_start + initrd_size) &&
+			initrd_start < (kernel_start + kernel_size))
+			return 0; /* initrd/initramfs overlaps kernel */
+	}
+
 	return 1;
 }
 #endif

arch/loongarch/mm/init.c

@@ -123,11 +123,7 @@ void arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap)
 {
 	unsigned long start_pfn = start >> PAGE_SHIFT;
 	unsigned long nr_pages = size >> PAGE_SHIFT;
-	struct page *page = pfn_to_page(start_pfn);
 
-	/* With altmap the first mapped page is offset from @start */
-	if (altmap)
-		page += vmem_altmap_offset(altmap);
 	__remove_pages(start_pfn, nr_pages, altmap);
 }
 #endif

drivers/firmware/efi/libstub/efi-stub-helper.c

@@ -79,6 +79,10 @@ efi_status_t efi_parse_options(char const *cmdline)
 			efi_noinitrd = true;
 		} else if (IS_ENABLED(CONFIG_X86_64) && !strcmp(param, "no5lvl")) {
 			efi_no5lvl = true;
+		} else if (IS_ENABLED(CONFIG_LOONGARCH) &&
+			   IS_ENABLED(CONFIG_HIBERNATION) &&
+			   !strcmp(param, "resume") && val) {
+			efi_nokaslr = true; /* LoongArch can't KASLR for hibernation */
 		} else if (IS_ENABLED(CONFIG_ARCH_HAS_MEM_ENCRYPT) &&
 			   !strcmp(param, "mem_encrypt") && val) {
 			if (parse_option_str(val, "on"))

drivers/firmware/efi/libstub/loongarch.c

@@ -23,6 +23,22 @@ void efi_cache_sync_image(unsigned long image_base, unsigned long alloc_size)
 	asm volatile ("ibar 0" ::: "memory");
 }
 
+unsigned long efi_get_kimg_kaslr_address(void)
+{
+	unsigned int random_offset = 0;
+
+#ifdef CONFIG_RANDOMIZE_BASE
+	if (!efi_nokaslr) {
+		efi_get_random_bytes(sizeof(random_offset), (u8 *)&random_offset);
+		random_offset ^= (random_get_entropy() << 16);
+		random_offset &= (CONFIG_RANDOMIZE_BASE_MAX_OFFSET - 1);
+		random_offset = ALIGN(random_offset + SZ_64K, SZ_64K);
+	}
+#endif
+
+	return PHYSADDR(VMLINUX_LOAD_ADDRESS) + random_offset;
+}
+
 struct exit_boot_struct {
 	efi_memory_desc_t	*runtime_map;
 	int			runtime_entry_count;