Merge tag 'riscv-for-linus-5.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V fixes from Palmer Dabbelt:

 - avoid dereferencing a null task pointer while walking the stack

 - fix the memory size in the HiFive Unleashed device tree

 - disable stack protectors when randstruct is enabled, which results in
   non-deterministic offsets during module builds

 - a pair of fixes to avoid relying on a constant physical memory base
   for the non-XIP builds

* tag 'riscv-for-linus-5.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  Revert "riscv: Remove CONFIG_PHYS_RAM_BASE_FIXED"
  riscv: Get rid of CONFIG_PHYS_RAM_BASE in kernel physical address conversion
  riscv: Disable STACKPROTECTOR_PER_TASK if GCC_PLUGIN_RANDSTRUCT is enabled
  riscv: dts: fix memory size for the SiFive HiFive Unmatched
  riscv: stacktrace: Fix NULL pointer dereference

Author: torvalds

arch/riscv/Kconfig

@@ -492,10 +492,16 @@ config CC_HAVE_STACKPROTECTOR_TLS
 
 config STACKPROTECTOR_PER_TASK
 	def_bool y
+	depends on !GCC_PLUGIN_RANDSTRUCT
 	depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_TLS
 
+config PHYS_RAM_BASE_FIXED
+	bool "Explicitly specified physical RAM address"
+	default n
+
 config PHYS_RAM_BASE
 	hex "Platform Physical RAM address"
+	depends on PHYS_RAM_BASE_FIXED
 	default "0x80000000"
 	help
 	  This is the physical address of RAM in the system. It has to be
@@ -508,6 +514,7 @@ config XIP_KERNEL
 	# This prevents XIP from being enabled by all{yes,mod}config, which
 	# fail to build since XIP doesn't support large kernels.
 	depends on !COMPILE_TEST
+	select PHYS_RAM_BASE_FIXED
 	help
 	  Execute-In-Place allows the kernel to run from non-volatile storage
 	  directly addressable by the CPU, such as NOR flash. This saves RAM

arch/riscv/boot/dts/sifive/hifive-unmatched-a00.dts

@@ -24,7 +24,7 @@
 
 	memory@80000000 {
 		device_type = "memory";
-		reg = <0x0 0x80000000 0x2 0x00000000>;
+		reg = <0x0 0x80000000 0x4 0x00000000>;
 	};
 
 	soc {

arch/riscv/include/asm/page.h

@@ -103,6 +103,7 @@ struct kernel_mapping {
 };
 
 extern struct kernel_mapping kernel_map;
+extern phys_addr_t phys_ram_base;
 
 #ifdef CONFIG_64BIT
 #define is_kernel_mapping(x)	\
@@ -113,9 +114,9 @@ extern struct kernel_mapping kernel_map;
 #define linear_mapping_pa_to_va(x)	((void *)((unsigned long)(x) + kernel_map.va_pa_offset))
 #define kernel_mapping_pa_to_va(y)	({						\
 	unsigned long _y = y;								\
-	(_y >= CONFIG_PHYS_RAM_BASE) ?							\
-		(void *)((unsigned long)(_y) + kernel_map.va_kernel_pa_offset + XIP_OFFSET) :	\
-		(void *)((unsigned long)(_y) + kernel_map.va_kernel_xip_pa_offset);		\
+	(IS_ENABLED(CONFIG_XIP_KERNEL) && _y < phys_ram_base) ?					\
+		(void *)((unsigned long)(_y) + kernel_map.va_kernel_xip_pa_offset) :		\
+		(void *)((unsigned long)(_y) + kernel_map.va_kernel_pa_offset + XIP_OFFSET);	\
 	})
 #define __pa_to_va_nodebug(x)		linear_mapping_pa_to_va(x)
 

arch/riscv/kernel/stacktrace.c

@@ -27,7 +27,7 @@ void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
 		fp = frame_pointer(regs);
 		sp = user_stack_pointer(regs);
 		pc = instruction_pointer(regs);
-	} else if (task == current) {
+	} else if (task == NULL || task == current) {
 		fp = (unsigned long)__builtin_frame_address(1);
 		sp = (unsigned long)__builtin_frame_address(0);
 		pc = (unsigned long)__builtin_return_address(0);

arch/riscv/mm/init.c

@@ -36,6 +36,9 @@ EXPORT_SYMBOL(kernel_map);
 #define kernel_map	(*(struct kernel_mapping *)XIP_FIXUP(&kernel_map))
 #endif
 
+phys_addr_t phys_ram_base __ro_after_init;
+EXPORT_SYMBOL(phys_ram_base);
+
 #ifdef CONFIG_XIP_KERNEL
 extern char _xiprom[], _exiprom[];
 #endif
@@ -160,7 +163,7 @@ static void __init setup_bootmem(void)
 	phys_addr_t vmlinux_end = __pa_symbol(&_end);
 	phys_addr_t vmlinux_start = __pa_symbol(&_start);
 	phys_addr_t __maybe_unused max_mapped_addr;
-	phys_addr_t dram_end;
+	phys_addr_t phys_ram_end;
 
 #ifdef CONFIG_XIP_KERNEL
 	vmlinux_start = __pa_symbol(&_sdata);
@@ -181,9 +184,12 @@ static void __init setup_bootmem(void)
 #endif
 	memblock_reserve(vmlinux_start, vmlinux_end - vmlinux_start);
 
-	dram_end = memblock_end_of_DRAM();
 
+	phys_ram_end = memblock_end_of_DRAM();
 #ifndef CONFIG_64BIT
+#ifndef CONFIG_XIP_KERNEL
+	phys_ram_base = memblock_start_of_DRAM();
+#endif
 	/*
 	 * memblock allocator is not aware of the fact that last 4K bytes of
 	 * the addressable memory can not be mapped because of IS_ERR_VALUE
@@ -194,12 +200,12 @@ static void __init setup_bootmem(void)
 	 * be done in create_kernel_page_table.
 	 */
 	max_mapped_addr = __pa(~(ulong)0);
-	if (max_mapped_addr == (dram_end - 1))
+	if (max_mapped_addr == (phys_ram_end - 1))
 		memblock_set_current_limit(max_mapped_addr - 4096);
 #endif
 
-	min_low_pfn = PFN_UP(memblock_start_of_DRAM());
-	max_low_pfn = max_pfn = PFN_DOWN(dram_end);
+	min_low_pfn = PFN_UP(phys_ram_base);
+	max_low_pfn = max_pfn = PFN_DOWN(phys_ram_end);
 
 	dma32_phys_limit = min(4UL * SZ_1G, (unsigned long)PFN_PHYS(max_low_pfn));
 	set_max_mapnr(max_low_pfn - ARCH_PFN_OFFSET);
@@ -558,6 +564,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
 	kernel_map.xiprom = (uintptr_t)CONFIG_XIP_PHYS_ADDR;
 	kernel_map.xiprom_sz = (uintptr_t)(&_exiprom) - (uintptr_t)(&_xiprom);
 
+	phys_ram_base = CONFIG_PHYS_RAM_BASE;
 	kernel_map.phys_addr = (uintptr_t)CONFIG_PHYS_RAM_BASE;
 	kernel_map.size = (uintptr_t)(&_end) - (uintptr_t)(&_sdata);