RISC-V Patches for the 5.6 Merge Window, Part 1

This tag contains a handful of patches that I'd like to target for this merge
 window:
 
 * Support for kasan.
 * 32-bit physical addresses on rv32i-based systems.
 * Support for CONFIG_DEBUG_VIRTUAL
 * DT entry for the FU540 GPIO controller, which has recently had a device
   driver merged.
 
 These boot a buildroot-based system on QEMU's virt board for me.
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Merge tag 'riscv-for-linus-5.6-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V updates from Palmer Dabbelt:
 "This contains a handful of patches for this merge window:

   - Support for kasan

   - 32-bit physical addresses on rv32i-based systems

   - Support for CONFIG_DEBUG_VIRTUAL

   - DT entry for the FU540 GPIO controller, which has recently had a
     device driver merged

  These boot a buildroot-based system on QEMU's virt board for me"

* tag 'riscv-for-linus-5.6-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  riscv: dts: Add DT support for SiFive FU540 GPIO driver
  riscv: mm: add support for CONFIG_DEBUG_VIRTUAL
  riscv: keep 32-bit kernel to 32-bit phys_addr_t
  kasan: Add riscv to KASAN documentation.
  riscv: Add KASAN support
  kasan: No KASAN's memmove check if archs don't have it.

Documentation/dev-tools/kasan.rst

@@ -21,8 +21,8 @@ global variables yet.
 
 Tag-based KASAN is only supported in Clang and requires version 7.0.0 or later.
 
-Currently generic KASAN is supported for the x86_64, arm64, xtensa and s390
-architectures, and tag-based KASAN is supported only for arm64.
+Currently generic KASAN is supported for the x86_64, arm64, xtensa, s390 and
+riscv architectures, and tag-based KASAN is supported only for arm64.
 
 Usage
 -----

arch/riscv/Kconfig

@@ -12,8 +12,6 @@ config 32BIT
 
 config RISCV
 	def_bool y
-	# even on 32-bit, physical (and DMA) addresses are > 32-bits
-	select PHYS_ADDR_T_64BIT
 	select OF
 	select OF_EARLY_FLATTREE
 	select OF_IRQ
@@ -57,6 +55,7 @@ config RISCV
 	select GENERIC_ARCH_TOPOLOGY if SMP
 	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_MMIOWB
+	select ARCH_HAS_DEBUG_VIRTUAL
 	select HAVE_EBPF_JIT if 64BIT
 	select EDAC_SUPPORT
 	select ARCH_HAS_GIGANTIC_PAGE
@@ -66,6 +65,7 @@ config RISCV
 	select HAVE_ARCH_MMAP_RND_BITS if MMU
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select HAVE_COPY_THREAD_TLS
+	select HAVE_ARCH_KASAN if MMU && 64BIT
 
 config ARCH_MMAP_RND_BITS_MIN
 	default 18 if 64BIT

arch/riscv/boot/dts/sifive/fu540-c000.dtsi

@@ -268,6 +268,19 @@
 			interrupts = <1 2 3>;
 			reg = <0x0 0x2010000 0x0 0x1000>;
 		};
-
+		gpio: gpio@10060000 {
+			compatible = "sifive,fu540-c000-gpio", "sifive,gpio0";
+			interrupt-parent = <&plic0>;
+			interrupts = <7>, <8>, <9>, <10>, <11>, <12>, <13>,
+				     <14>, <15>, <16>, <17>, <18>, <19>, <20>,
+				     <21>, <22>;
+			reg = <0x0 0x10060000 0x0 0x1000>;
+			gpio-controller;
+			#gpio-cells = <2>;
+			interrupt-controller;
+			#interrupt-cells = <2>;
+			clocks = <&prci PRCI_CLK_TLCLK>;
+			status = "disabled";
+		};
 	};
 };

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

@@ -94,3 +94,7 @@
 &pwm1 {
 	status = "okay";
 };
+
+&gpio {
+	status = "okay";
+};

arch/riscv/include/asm/kasan.h

@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2019 Andes Technology Corporation */
+
+#ifndef __ASM_KASAN_H
+#define __ASM_KASAN_H
+
+#ifndef __ASSEMBLY__
+
+#ifdef CONFIG_KASAN
+
+#include <asm/pgtable.h>
+
+#define KASAN_SHADOW_SCALE_SHIFT	3
+
+#define KASAN_SHADOW_SIZE	(UL(1) << (38 - KASAN_SHADOW_SCALE_SHIFT))
+#define KASAN_SHADOW_START	0xffffffc000000000 /* 2^64 - 2^38 */
+#define KASAN_SHADOW_END	(KASAN_SHADOW_START + KASAN_SHADOW_SIZE)
+
+#define KASAN_SHADOW_OFFSET	(KASAN_SHADOW_END - (1ULL << \
+					(64 - KASAN_SHADOW_SCALE_SHIFT)))
+
+void kasan_init(void);
+asmlinkage void kasan_early_init(void);
+
+#endif
+#endif
+#endif /* __ASM_KASAN_H */

arch/riscv/include/asm/page.h

@@ -100,8 +100,20 @@ extern unsigned long pfn_base;
 extern unsigned long max_low_pfn;
 extern unsigned long min_low_pfn;
 
-#define __pa(x)		((unsigned long)(x) - va_pa_offset)
-#define __va(x)		((void *)((unsigned long) (x) + va_pa_offset))
+#define __pa_to_va_nodebug(x)	((void *)((unsigned long) (x) + va_pa_offset))
+#define __va_to_pa_nodebug(x)	((unsigned long)(x) - va_pa_offset)
+
+#ifdef CONFIG_DEBUG_VIRTUAL
+extern phys_addr_t __virt_to_phys(unsigned long x);
+extern phys_addr_t __phys_addr_symbol(unsigned long x);
+#else
+#define __virt_to_phys(x)	__va_to_pa_nodebug(x)
+#define __phys_addr_symbol(x)	__va_to_pa_nodebug(x)
+#endif /* CONFIG_DEBUG_VIRTUAL */
+
+#define __pa_symbol(x)	__phys_addr_symbol(RELOC_HIDE((unsigned long)(x), 0))
+#define __pa(x)		__virt_to_phys((unsigned long)(x))
+#define __va(x)		((void *)__pa_to_va_nodebug((phys_addr_t)(x)))
 
 #define phys_to_pfn(phys)	(PFN_DOWN(phys))
 #define pfn_to_phys(pfn)	(PFN_PHYS(pfn))

arch/riscv/include/asm/pgtable-64.h

@@ -58,6 +58,11 @@ static inline unsigned long pud_page_vaddr(pud_t pud)
 	return (unsigned long)pfn_to_virt(pud_val(pud) >> _PAGE_PFN_SHIFT);
 }
 
+static inline struct page *pud_page(pud_t pud)
+{
+	return pfn_to_page(pud_val(pud) >> _PAGE_PFN_SHIFT);
+}
+
 #define pmd_index(addr) (((addr) >> PMD_SHIFT) & (PTRS_PER_PMD - 1))
 
 static inline pmd_t *pmd_offset(pud_t *pud, unsigned long addr)

arch/riscv/include/asm/string.h

@@ -11,8 +11,17 @@
 
 #define __HAVE_ARCH_MEMSET
 extern asmlinkage void *memset(void *, int, size_t);
+extern asmlinkage void *__memset(void *, int, size_t);
 
 #define __HAVE_ARCH_MEMCPY
 extern asmlinkage void *memcpy(void *, const void *, size_t);
+extern asmlinkage void *__memcpy(void *, const void *, size_t);
 
+/* For those files which don't want to check by kasan. */
+#if defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__)
+
+#define memcpy(dst, src, len) __memcpy(dst, src, len)
+#define memset(s, c, n) __memset(s, c, n)
+
+#endif
 #endif /* _ASM_RISCV_STRING_H */

arch/riscv/kernel/head.S

@@ -121,6 +121,9 @@ clear_bss_done:
 	sw zero, TASK_TI_CPU(tp)
 	la sp, init_thread_union + THREAD_SIZE
 
+#ifdef CONFIG_KASAN
+	call kasan_early_init
+#endif
 	/* Start the kernel */
 	call parse_dtb
 	tail start_kernel

arch/riscv/kernel/riscv_ksyms.c

@@ -11,3 +11,5 @@
  */
 EXPORT_SYMBOL(memset);
 EXPORT_SYMBOL(memcpy);
+EXPORT_SYMBOL(__memset);
+EXPORT_SYMBOL(__memcpy);

arch/riscv/kernel/setup.c

@@ -24,6 +24,7 @@
 #include <asm/smp.h>
 #include <asm/tlbflush.h>
 #include <asm/thread_info.h>
+#include <asm/kasan.h>
 
 #include "head.h"
 
@@ -74,6 +75,10 @@ void __init setup_arch(char **cmdline_p)
 	swiotlb_init(1);
 #endif
 
+#ifdef CONFIG_KASAN
+	kasan_init();
+#endif
+
 #ifdef CONFIG_SMP
 	setup_smp();
 #endif

arch/riscv/kernel/vmlinux.lds.S

@@ -46,6 +46,7 @@ SECTIONS
 		KPROBES_TEXT
 		ENTRY_TEXT
 		IRQENTRY_TEXT
+		SOFTIRQENTRY_TEXT
 		*(.fixup)
 		_etext = .;
 	}

arch/riscv/lib/memcpy.S

@@ -7,7 +7,8 @@
 #include <asm/asm.h>
 
 /* void *memcpy(void *, const void *, size_t) */
-ENTRY(memcpy)
+ENTRY(__memcpy)
+WEAK(memcpy)
 	move t6, a0  /* Preserve return value */
 
 	/* Defer to byte-oriented copy for small sizes */
@@ -104,4 +105,4 @@ ENTRY(memcpy)
 	bltu a1, a3, 5b
 6:
 	ret
-END(memcpy)
+END(__memcpy)

arch/riscv/lib/memset.S

@@ -8,7 +8,8 @@
 #include <asm/asm.h>
 
 /* void *memset(void *, int, size_t) */
-ENTRY(memset)
+ENTRY(__memset)
+WEAK(memset)
 	move t0, a0  /* Preserve return value */
 
 	/* Defer to byte-oriented fill for small sizes */
@@ -109,4 +110,4 @@ ENTRY(memset)
 	bltu t0, a3, 5b
 6:
 	ret
-END(memset)
+END(__memset)

arch/riscv/mm/Makefile

@@ -15,3 +15,11 @@ ifeq ($(CONFIG_MMU),y)
 obj-$(CONFIG_SMP) += tlbflush.o
 endif
 obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
+obj-$(CONFIG_KASAN)   += kasan_init.o
+
+ifdef CONFIG_KASAN
+KASAN_SANITIZE_kasan_init.o := n
+KASAN_SANITIZE_init.o := n
+endif
+
+obj-$(CONFIG_DEBUG_VIRTUAL) += physaddr.o

arch/riscv/mm/kasan_init.c

@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2019 Andes Technology Corporation
+
+#include <linux/pfn.h>
+#include <linux/init_task.h>
+#include <linux/kasan.h>
+#include <linux/kernel.h>
+#include <linux/memblock.h>
+#include <asm/tlbflush.h>
+#include <asm/pgtable.h>
+#include <asm/fixmap.h>
+
+extern pgd_t early_pg_dir[PTRS_PER_PGD];
+asmlinkage void __init kasan_early_init(void)
+{
+	uintptr_t i;
+	pgd_t *pgd = early_pg_dir + pgd_index(KASAN_SHADOW_START);
+
+	for (i = 0; i < PTRS_PER_PTE; ++i)
+		set_pte(kasan_early_shadow_pte + i,
+			mk_pte(virt_to_page(kasan_early_shadow_page),
+			PAGE_KERNEL));
+
+	for (i = 0; i < PTRS_PER_PMD; ++i)
+		set_pmd(kasan_early_shadow_pmd + i,
+		 pfn_pmd(PFN_DOWN(__pa((uintptr_t)kasan_early_shadow_pte)),
+			__pgprot(_PAGE_TABLE)));
+
+	for (i = KASAN_SHADOW_START; i < KASAN_SHADOW_END;
+	     i += PGDIR_SIZE, ++pgd)
+		set_pgd(pgd,
+		 pfn_pgd(PFN_DOWN(__pa(((uintptr_t)kasan_early_shadow_pmd))),
+			__pgprot(_PAGE_TABLE)));
+
+	/* init for swapper_pg_dir */
+	pgd = pgd_offset_k(KASAN_SHADOW_START);
+
+	for (i = KASAN_SHADOW_START; i < KASAN_SHADOW_END;
+	     i += PGDIR_SIZE, ++pgd)
+		set_pgd(pgd,
+		 pfn_pgd(PFN_DOWN(__pa(((uintptr_t)kasan_early_shadow_pmd))),
+			__pgprot(_PAGE_TABLE)));
+
+	flush_tlb_all();
+}
+
+static void __init populate(void *start, void *end)
+{
+	unsigned long i;
+	unsigned long vaddr = (unsigned long)start & PAGE_MASK;
+	unsigned long vend = PAGE_ALIGN((unsigned long)end);
+	unsigned long n_pages = (vend - vaddr) / PAGE_SIZE;
+	unsigned long n_pmds =
+		(n_pages % PTRS_PER_PTE) ? n_pages / PTRS_PER_PTE + 1 :
+						n_pages / PTRS_PER_PTE;
+	pgd_t *pgd = pgd_offset_k(vaddr);
+	pmd_t *pmd = memblock_alloc(n_pmds * sizeof(pmd_t), PAGE_SIZE);
+	pte_t *pte = memblock_alloc(n_pages * sizeof(pte_t), PAGE_SIZE);
+
+	for (i = 0; i < n_pages; i++) {
+		phys_addr_t phys = memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
+
+		set_pte(pte + i, pfn_pte(PHYS_PFN(phys), PAGE_KERNEL));
+	}
+
+	for (i = 0; i < n_pmds; ++pgd, i += PTRS_PER_PMD)
+		set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(((uintptr_t)(pmd + i)))),
+				__pgprot(_PAGE_TABLE)));
+
+	for (i = 0; i < n_pages; ++pmd, i += PTRS_PER_PTE)
+		set_pmd(pmd, pfn_pmd(PFN_DOWN(__pa((uintptr_t)(pte + i))),
+				__pgprot(_PAGE_TABLE)));
+
+	flush_tlb_all();
+	memset(start, 0, end - start);
+}
+
+void __init kasan_init(void)
+{
+	struct memblock_region *reg;
+	unsigned long i;
+
+	kasan_populate_early_shadow((void *)KASAN_SHADOW_START,
+			(void *)kasan_mem_to_shadow((void *)VMALLOC_END));
+
+	for_each_memblock(memory, reg) {
+		void *start = (void *)__va(reg->base);
+		void *end = (void *)__va(reg->base + reg->size);
+
+		if (start >= end)
+			break;
+
+		populate(kasan_mem_to_shadow(start),
+			 kasan_mem_to_shadow(end));
+	};
+
+	for (i = 0; i < PTRS_PER_PTE; i++)
+		set_pte(&kasan_early_shadow_pte[i],
+			mk_pte(virt_to_page(kasan_early_shadow_page),
+			__pgprot(_PAGE_PRESENT | _PAGE_READ | _PAGE_ACCESSED)));
+
+	memset(kasan_early_shadow_page, 0, PAGE_SIZE);
+	init_task.kasan_depth = 0;
+}

arch/riscv/mm/physaddr.c

@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/types.h>
+#include <linux/mmdebug.h>
+#include <linux/mm.h>
+#include <asm/page.h>
+#include <asm/sections.h>
+
+phys_addr_t __virt_to_phys(unsigned long x)
+{
+	phys_addr_t y = x - PAGE_OFFSET;
+
+	/*
+	 * Boundary checking aginst the kernel linear mapping space.
+	 */
+	WARN(y >= KERN_VIRT_SIZE,
+	     "virt_to_phys used for non-linear address: %pK (%pS)\n",
+	     (void *)x, (void *)x);
+
+	return __va_to_pa_nodebug(x);
+}
+EXPORT_SYMBOL(__virt_to_phys);
+
+phys_addr_t __phys_addr_symbol(unsigned long x)
+{
+	unsigned long kernel_start = (unsigned long)PAGE_OFFSET;
+	unsigned long kernel_end = (unsigned long)_end;
+
+	/*
+	 * Boundary checking aginst the kernel image mapping.
+	 * __pa_symbol should only be used on kernel symbol addresses.
+	 */
+	VIRTUAL_BUG_ON(x < kernel_start || x > kernel_end);
+
+	return __va_to_pa_nodebug(x);
+}
+EXPORT_SYMBOL(__phys_addr_symbol);

mm/kasan/common.c

@@ -110,6 +110,7 @@ void *memset(void *addr, int c, size_t len)
 	return __memset(addr, c, len);
 }
 
+#ifdef __HAVE_ARCH_MEMMOVE
 #undef memmove
 void *memmove(void *dest, const void *src, size_t len)
 {
@@ -118,6 +119,7 @@ void *memmove(void *dest, const void *src, size_t len)
 
 	return __memmove(dest, src, len);
 }
+#endif
 
 #undef memcpy
 void *memcpy(void *dest, const void *src, size_t len)