Merge tag 'x86-core-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 debug fixlets from Ingo Molnar:
 "Improve x86 debuggability: print registers with the same log level as
  the backtrace"

* tag 'x86-core-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/dumpstack: Show registers dump with trace's log level
  x86/dumpstack: Add log_lvl to __show_regs()
  x86/dumpstack: Add log_lvl to show_iret_regs()

4 files changed, 57 insertions, 51 deletions

diff --git a/arch/x86/include/asm/kdebug.h b/arch/x86/include/asm/kdebug.h
index 247ab14c6309..d1514e70477b 100644
--- a/arch/x86/include/asm/kdebug.h
+++ b/arch/x86/include/asm/kdebug.h
@@ -36,8 +36,9 @@ extern void die(const char *, struct pt_regs *,long);
 void die_addr(const char *str, struct pt_regs *regs, long err, long gp_addr);
 extern int __must_check __die(const char *, struct pt_regs *, long);
 extern void show_stack_regs(struct pt_regs *regs);
-extern void __show_regs(struct pt_regs *regs, enum show_regs_mode);
-extern void show_iret_regs(struct pt_regs *regs);
+extern void __show_regs(struct pt_regs *regs, enum show_regs_mode,
+			const char *log_lvl);
+extern void show_iret_regs(struct pt_regs *regs, const char *log_lvl);
 extern unsigned long oops_begin(void);
 extern void oops_end(unsigned long, struct pt_regs *, int signr);
 
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index 7401cc12c3cc..48ce44576947 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -133,15 +133,15 @@ void show_ip(struct pt_regs *regs, const char *loglvl)
 	show_opcodes(regs, loglvl);
 }
 
-void show_iret_regs(struct pt_regs *regs)
+void show_iret_regs(struct pt_regs *regs, const char *log_lvl)
 {
-	show_ip(regs, KERN_DEFAULT);
-	printk(KERN_DEFAULT "RSP: %04x:%016lx EFLAGS: %08lx", (int)regs->ss,
+	show_ip(regs, log_lvl);
+	printk("%sRSP: %04x:%016lx EFLAGS: %08lx", log_lvl, (int)regs->ss,
 		regs->sp, regs->flags);
 }
 
 static void show_regs_if_on_stack(struct stack_info *info, struct pt_regs *regs,
-				  bool partial)
+				  bool partial, const char *log_lvl)
 {
 	/*
 	 * These on_stack() checks aren't strictly necessary: the unwind code
@@ -153,7 +153,7 @@ static void show_regs_if_on_stack(struct stack_info *info, struct pt_regs *regs,
 	 * they can be printed in the right context.
 	 */
 	if (!partial && on_stack(info, regs, sizeof(*regs))) {
-		__show_regs(regs, SHOW_REGS_SHORT);
+		__show_regs(regs, SHOW_REGS_SHORT, log_lvl);
 
 	} else if (partial && on_stack(info, (void *)regs + IRET_FRAME_OFFSET,
 				       IRET_FRAME_SIZE)) {
@@ -162,7 +162,7 @@ static void show_regs_if_on_stack(struct stack_info *info, struct pt_regs *regs,
 		 * full pt_regs might not have been saved yet.  In that case
 		 * just print the iret frame.
 		 */
-		show_iret_regs(regs);
+		show_iret_regs(regs, log_lvl);
 	}
 }
 
@@ -217,7 +217,7 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
 			printk("%s <%s>\n", log_lvl, stack_name);
 
 		if (regs)
-			show_regs_if_on_stack(&stack_info, regs, partial);
+			show_regs_if_on_stack(&stack_info, regs, partial, log_lvl);
 
 		/*
 		 * Scan the stack, printing any text addresses we find.  At the
@@ -278,7 +278,7 @@ next:
 			/* if the frame has entry regs, print them */
 			regs = unwind_get_entry_regs(&state, &partial);
 			if (regs)
-				show_regs_if_on_stack(&stack_info, regs, partial);
+				show_regs_if_on_stack(&stack_info, regs, partial, log_lvl);
 		}
 
 		if (stack_name)
@@ -352,7 +352,7 @@ void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
 	oops_exit();
 
 	/* Executive summary in case the oops scrolled away */
-	__show_regs(&exec_summary_regs, SHOW_REGS_ALL);
+	__show_regs(&exec_summary_regs, SHOW_REGS_ALL, KERN_DEFAULT);
 
 	if (!signr)
 		return;
@@ -444,9 +444,12 @@ void die_addr(const char *str, struct pt_regs *regs, long err, long gp_addr)
 
 void show_regs(struct pt_regs *regs)
 {
+	enum show_regs_mode print_kernel_regs;
+
 	show_regs_print_info(KERN_DEFAULT);
 
-	__show_regs(regs, user_mode(regs) ? SHOW_REGS_USER : SHOW_REGS_ALL);
+	print_kernel_regs = user_mode(regs) ? SHOW_REGS_USER : SHOW_REGS_ALL;
+	__show_regs(regs, print_kernel_regs, KERN_DEFAULT);
 
 	/*
 	 * When in-kernel, we also print out the stack at the time of the fault..
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index acfd6d2a0cbf..4f2f54e1281c 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -56,7 +56,8 @@
 
 #include "process.h"
 
-void __show_regs(struct pt_regs *regs, enum show_regs_mode mode)
+void __show_regs(struct pt_regs *regs, enum show_regs_mode mode,
+		 const char *log_lvl)
 {
 	unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L;
 	unsigned long d0, d1, d2, d3, d6, d7;
@@ -67,14 +68,14 @@ void __show_regs(struct pt_regs *regs, enum show_regs_mode mode)
 	else
 		savesegment(gs, gs);
 
-	show_ip(regs, KERN_DEFAULT);
+	show_ip(regs, log_lvl);
 
-	printk(KERN_DEFAULT "EAX: %08lx EBX: %08lx ECX: %08lx EDX: %08lx\n",
-		regs->ax, regs->bx, regs->cx, regs->dx);
-	printk(KERN_DEFAULT "ESI: %08lx EDI: %08lx EBP: %08lx ESP: %08lx\n",
-		regs->si, regs->di, regs->bp, regs->sp);
-	printk(KERN_DEFAULT "DS: %04x ES: %04x FS: %04x GS: %04x SS: %04x EFLAGS: %08lx\n",
-	       (u16)regs->ds, (u16)regs->es, (u16)regs->fs, gs, regs->ss, regs->flags);
+	printk("%sEAX: %08lx EBX: %08lx ECX: %08lx EDX: %08lx\n",
+		log_lvl, regs->ax, regs->bx, regs->cx, regs->dx);
+	printk("%sESI: %08lx EDI: %08lx EBP: %08lx ESP: %08lx\n",
+		log_lvl, regs->si, regs->di, regs->bp, regs->sp);
+	printk("%sDS: %04x ES: %04x FS: %04x GS: %04x SS: %04x EFLAGS: %08lx\n",
+	       log_lvl, (u16)regs->ds, (u16)regs->es, (u16)regs->fs, gs, regs->ss, regs->flags);
 
 	if (mode != SHOW_REGS_ALL)
 		return;
@@ -83,8 +84,8 @@ void __show_regs(struct pt_regs *regs, enum show_regs_mode mode)
 	cr2 = read_cr2();
 	cr3 = __read_cr3();
 	cr4 = __read_cr4();
-	printk(KERN_DEFAULT "CR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n",
-			cr0, cr2, cr3, cr4);
+	printk("%sCR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n",
+		log_lvl, cr0, cr2, cr3, cr4);
 
 	get_debugreg(d0, 0);
 	get_debugreg(d1, 1);
@@ -98,10 +99,10 @@ void __show_regs(struct pt_regs *regs, enum show_regs_mode mode)
 	    (d6 == DR6_RESERVED) && (d7 == 0x400))
 		return;
 
-	printk(KERN_DEFAULT "DR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n",
-			d0, d1, d2, d3);
-	printk(KERN_DEFAULT "DR6: %08lx DR7: %08lx\n",
-			d6, d7);
+	printk("%sDR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n",
+		log_lvl, d0, d1, d2, d3);
+	printk("%sDR6: %08lx DR7: %08lx\n",
+		log_lvl, d6, d7);
 }
 
 void release_thread(struct task_struct *dead_task)
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 9a97415b2139..04d201ad3a1e 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -62,30 +62,31 @@
 #include "process.h"
 
 /* Prints also some state that isn't saved in the pt_regs */
-void __show_regs(struct pt_regs *regs, enum show_regs_mode mode)
+void __show_regs(struct pt_regs *regs, enum show_regs_mode mode,
+		 const char *log_lvl)
 {
 	unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L, fs, gs, shadowgs;
 	unsigned long d0, d1, d2, d3, d6, d7;
 	unsigned int fsindex, gsindex;
 	unsigned int ds, es;
 
-	show_iret_regs(regs);
+	show_iret_regs(regs, log_lvl);
 
 	if (regs->orig_ax != -1)
 		pr_cont(" ORIG_RAX: %016lx\n", regs->orig_ax);
 	else
 		pr_cont("\n");
 
-	printk(KERN_DEFAULT "RAX: %016lx RBX: %016lx RCX: %016lx\n",
-	       regs->ax, regs->bx, regs->cx);
-	printk(KERN_DEFAULT "RDX: %016lx RSI: %016lx RDI: %016lx\n",
-	       regs->dx, regs->si, regs->di);
-	printk(KERN_DEFAULT "RBP: %016lx R08: %016lx R09: %016lx\n",
-	       regs->bp, regs->r8, regs->r9);
-	printk(KERN_DEFAULT "R10: %016lx R11: %016lx R12: %016lx\n",
-	       regs->r10, regs->r11, regs->r12);
-	printk(KERN_DEFAULT "R13: %016lx R14: %016lx R15: %016lx\n",
-	       regs->r13, regs->r14, regs->r15);
+	printk("%sRAX: %016lx RBX: %016lx RCX: %016lx\n",
+	       log_lvl, regs->ax, regs->bx, regs->cx);
+	printk("%sRDX: %016lx RSI: %016lx RDI: %016lx\n",
+	       log_lvl, regs->dx, regs->si, regs->di);
+	printk("%sRBP: %016lx R08: %016lx R09: %016lx\n",
+	       log_lvl, regs->bp, regs->r8, regs->r9);
+	printk("%sR10: %016lx R11: %016lx R12: %016lx\n",
+	       log_lvl, regs->r10, regs->r11, regs->r12);
+	printk("%sR13: %016lx R14: %016lx R15: %016lx\n",
+	       log_lvl, regs->r13, regs->r14, regs->r15);
 
 	if (mode == SHOW_REGS_SHORT)
 		return;
@@ -93,8 +94,8 @@ void __show_regs(struct pt_regs *regs, enum show_regs_mode mode)
 	if (mode == SHOW_REGS_USER) {
 		rdmsrl(MSR_FS_BASE, fs);
 		rdmsrl(MSR_KERNEL_GS_BASE, shadowgs);
-		printk(KERN_DEFAULT "FS:  %016lx GS:  %016lx\n",
-		       fs, shadowgs);
+		printk("%sFS:  %016lx GS:  %016lx\n",
+		       log_lvl, fs, shadowgs);
 		return;
 	}
 
@@ -112,12 +113,12 @@ void __show_regs(struct pt_regs *regs, enum show_regs_mode mode)
 	cr3 = __read_cr3();
 	cr4 = __read_cr4();
 
-	printk(KERN_DEFAULT "FS:  %016lx(%04x) GS:%016lx(%04x) knlGS:%016lx\n",
-	       fs, fsindex, gs, gsindex, shadowgs);
-	printk(KERN_DEFAULT "CS:  %04lx DS: %04x ES: %04x CR0: %016lx\n", regs->cs, ds,
-			es, cr0);
-	printk(KERN_DEFAULT "CR2: %016lx CR3: %016lx CR4: %016lx\n", cr2, cr3,
-			cr4);
+	printk("%sFS:  %016lx(%04x) GS:%016lx(%04x) knlGS:%016lx\n",
+	       log_lvl, fs, fsindex, gs, gsindex, shadowgs);
+	printk("%sCS:  %04lx DS: %04x ES: %04x CR0: %016lx\n",
+		log_lvl, regs->cs, ds, es, cr0);
+	printk("%sCR2: %016lx CR3: %016lx CR4: %016lx\n",
+		log_lvl, cr2, cr3, cr4);
 
 	get_debugreg(d0, 0);
 	get_debugreg(d1, 1);
@@ -129,14 +130,14 @@ void __show_regs(struct pt_regs *regs, enum show_regs_mode mode)
 	/* Only print out debug registers if they are in their non-default state. */
 	if (!((d0 == 0) && (d1 == 0) && (d2 == 0) && (d3 == 0) &&
 	    (d6 == DR6_RESERVED) && (d7 == 0x400))) {
-		printk(KERN_DEFAULT "DR0: %016lx DR1: %016lx DR2: %016lx\n",
-		       d0, d1, d2);
-		printk(KERN_DEFAULT "DR3: %016lx DR6: %016lx DR7: %016lx\n",
-		       d3, d6, d7);
+		printk("%sDR0: %016lx DR1: %016lx DR2: %016lx\n",
+		       log_lvl, d0, d1, d2);
+		printk("%sDR3: %016lx DR6: %016lx DR7: %016lx\n",
+		       log_lvl, d3, d6, d7);
 	}
 
 	if (boot_cpu_has(X86_FEATURE_OSPKE))
-		printk(KERN_DEFAULT "PKRU: %08x\n", read_pkru());
+		printk("%sPKRU: %08x\n", log_lvl, read_pkru());
 }
 
 void release_thread(struct task_struct *dead_task)