Merge tag 'mips_fixes_4.19_2' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux

Paul writes:
  "A few MIPS fixes for 4.19:

   - Avoid suboptimal placement of our VDSO when using the legacy mmap
     layout, which can prevent statically linked programs that were able
     to allocate large amounts of memory using the brk syscall prior to
     the introduction of our VDSO from functioning correctly.

   - Fix up CONFIG_CMDLINE handling for platforms which ought to ignore
     DT arguments but have incorrectly used them & lost other arguments
     since v3.16.

   - Fix a path in MAINTAINERS to use valid wildcards.

   - Fixup a regression from v4.17 in memset() for systems using
     CPU_DADDI_WORKAROUNDS."

* tag 'mips_fixes_4.19_2' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
  MIPS: memset: Fix CPU_DADDI_WORKAROUNDS `small_fixup' regression
  MAINTAINERS: MIPS/LOONGSON2 ARCHITECTURE - Use the normal wildcard style
  MIPS: Fix CONFIG_CMDLINE handling
  MIPS: VDSO: Always map near top of user memory

5 files changed, 78 insertions, 27 deletions

diff --git a/arch/mips/include/asm/processor.h b/arch/mips/include/asm/processor.h
index b2fa62922d88..49d6046ca1d0 100644
--- a/arch/mips/include/asm/processor.h
+++ b/arch/mips/include/asm/processor.h
@@ -13,6 +13,7 @@
 
 #include <linux/atomic.h>
 #include <linux/cpumask.h>
+#include <linux/sizes.h>
 #include <linux/threads.h>
 
 #include <asm/cachectl.h>
@@ -80,11 +81,10 @@ extern unsigned int vced_count, vcei_count;
 
 #endif
 
-/*
- * One page above the stack is used for branch delay slot "emulation".
- * See dsemul.c for details.
- */
-#define STACK_TOP	((TASK_SIZE & PAGE_MASK) - PAGE_SIZE)
+#define VDSO_RANDOMIZE_SIZE	(TASK_IS_32BIT_ADDR ? SZ_1M : SZ_256M)
+
+extern unsigned long mips_stack_top(void);
+#define STACK_TOP		mips_stack_top()
 
 /*
  * This decides where the kernel will search for a free chunk of vm
diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index 8fc69891e117..d4f7fd4550e1 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -32,6 +32,7 @@
 #include <linux/nmi.h>
 #include <linux/cpu.h>
 
+#include <asm/abi.h>
 #include <asm/asm.h>
 #include <asm/bootinfo.h>
 #include <asm/cpu.h>
@@ -39,6 +40,7 @@
 #include <asm/dsp.h>
 #include <asm/fpu.h>
 #include <asm/irq.h>
+#include <asm/mips-cps.h>
 #include <asm/msa.h>
 #include <asm/pgtable.h>
 #include <asm/mipsregs.h>
@@ -645,6 +647,29 @@ out:
 	return pc;
 }
 
+unsigned long mips_stack_top(void)
+{
+	unsigned long top = TASK_SIZE & PAGE_MASK;
+
+	/* One page for branch delay slot "emulation" */
+	top -= PAGE_SIZE;
+
+	/* Space for the VDSO, data page & GIC user page */
+	top -= PAGE_ALIGN(current->thread.abi->vdso->size);
+	top -= PAGE_SIZE;
+	top -= mips_gic_present() ? PAGE_SIZE : 0;
+
+	/* Space for cache colour alignment */
+	if (cpu_has_dc_aliases)
+		top -= shm_align_mask + 1;
+
+	/* Space to randomize the VDSO base */
+	if (current->flags & PF_RANDOMIZE)
+		top -= VDSO_RANDOMIZE_SIZE;
+
+	return top;
+}
+
 /*
  * Don't forget that the stack pointer must be aligned on a 8 bytes
  * boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index c71d1eb7da59..8aaaa42f91ed 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -846,6 +846,34 @@ static void __init arch_mem_init(char **cmdline_p)
 	struct memblock_region *reg;
 	extern void plat_mem_setup(void);
 
+	/*
+	 * Initialize boot_command_line to an innocuous but non-empty string in
+	 * order to prevent early_init_dt_scan_chosen() from copying
+	 * CONFIG_CMDLINE into it without our knowledge. We handle
+	 * CONFIG_CMDLINE ourselves below & don't want to duplicate its
+	 * content because repeating arguments can be problematic.
+	 */
+	strlcpy(boot_command_line, " ", COMMAND_LINE_SIZE);
+
+	/* call board setup routine */
+	plat_mem_setup();
+
+	/*
+	 * Make sure all kernel memory is in the maps.  The "UP" and
+	 * "DOWN" are opposite for initdata since if it crosses over
+	 * into another memory section you don't want that to be
+	 * freed when the initdata is freed.
+	 */
+	arch_mem_addpart(PFN_DOWN(__pa_symbol(&_text)) << PAGE_SHIFT,
+			 PFN_UP(__pa_symbol(&_edata)) << PAGE_SHIFT,
+			 BOOT_MEM_RAM);
+	arch_mem_addpart(PFN_UP(__pa_symbol(&__init_begin)) << PAGE_SHIFT,
+			 PFN_DOWN(__pa_symbol(&__init_end)) << PAGE_SHIFT,
+			 BOOT_MEM_INIT_RAM);
+
+	pr_info("Determined physical RAM map:\n");
+	print_memory_map();
+
 #if defined(CONFIG_CMDLINE_BOOL) && defined(CONFIG_CMDLINE_OVERRIDE)
 	strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
 #else
@@ -873,26 +901,6 @@ static void __init arch_mem_init(char **cmdline_p)
 	}
 #endif
 #endif
-
-	/* call board setup routine */
-	plat_mem_setup();
-
-	/*
-	 * Make sure all kernel memory is in the maps.  The "UP" and
-	 * "DOWN" are opposite for initdata since if it crosses over
-	 * into another memory section you don't want that to be
-	 * freed when the initdata is freed.
-	 */
-	arch_mem_addpart(PFN_DOWN(__pa_symbol(&_text)) << PAGE_SHIFT,
-			 PFN_UP(__pa_symbol(&_edata)) << PAGE_SHIFT,
-			 BOOT_MEM_RAM);
-	arch_mem_addpart(PFN_UP(__pa_symbol(&__init_begin)) << PAGE_SHIFT,
-			 PFN_DOWN(__pa_symbol(&__init_end)) << PAGE_SHIFT,
-			 BOOT_MEM_INIT_RAM);
-
-	pr_info("Determined physical RAM map:\n");
-	print_memory_map();
-
 	strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
 
 	*cmdline_p = command_line;
diff --git a/arch/mips/kernel/vdso.c b/arch/mips/kernel/vdso.c
index 8f845f6e5f42..48a9c6b90e07 100644
--- a/arch/mips/kernel/vdso.c
+++ b/arch/mips/kernel/vdso.c
@@ -15,6 +15,7 @@
 #include <linux/ioport.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
+#include <linux/random.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/timekeeper_internal.h>
@@ -97,6 +98,21 @@ void update_vsyscall_tz(void)
 	}
 }
 
+static unsigned long vdso_base(void)
+{
+	unsigned long base;
+
+	/* Skip the delay slot emulation page */
+	base = STACK_TOP + PAGE_SIZE;
+
+	if (current->flags & PF_RANDOMIZE) {
+		base += get_random_int() & (VDSO_RANDOMIZE_SIZE - 1);
+		base = PAGE_ALIGN(base);
+	}
+
+	return base;
+}
+
 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 {
 	struct mips_vdso_image *image = current->thread.abi->vdso;
@@ -137,7 +153,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 	if (cpu_has_dc_aliases)
 		size += shm_align_mask + 1;
 
-	base = get_unmapped_area(NULL, 0, size, 0, 0);
+	base = get_unmapped_area(NULL, vdso_base(), size, 0, 0);
 	if (IS_ERR_VALUE(base)) {
 		ret = base;
 		goto out;
diff --git a/arch/mips/lib/memset.S b/arch/mips/lib/memset.S
index 3a6f34ef5ffc..069acec3df9f 100644
--- a/arch/mips/lib/memset.S
+++ b/arch/mips/lib/memset.S
@@ -280,9 +280,11 @@
 	 * unset_bytes = end_addr - current_addr + 1
 	 *      a2     =    t1    -      a0      + 1
 	 */
+	.set		reorder
 	PTR_SUBU	a2, t1, a0
+	PTR_ADDIU	a2, 1
 	jr		ra
-	 PTR_ADDIU	a2, 1
+	.set		noreorder
 
 	.endm