Merge tag 'riscv-for-linux-5.6-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V fixes from Palmer Dabbelt:
 "This contains a handful of RISC-V related fixes that I've collected
  and would like to target for 5.6-rc4:

   - A fix to set up the PMPs on boot, which allows the kernel to access
     memory on systems that don't set up permissive PMPs before getting
     to Linux. This only effects machine-mode kernels, which currently
     means only NOMMU kernels.

   - A fix to avoid enabling supervisor-mode interrupts when running in
     machine-mode, also only for NOMMU kernels.

   - A pair of fixes to our KASAN support to avoid corrupting memory.

   - A gitignore fix.

  This boots on QEMU's virt board for me"

* tag 'riscv-for-linux-5.6-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  riscv: adjust the indent
  riscv: allocate a complete page size for each page table
  riscv: Fix gitignore
  RISC-V: Don't enable all interrupts in trap_init()
  riscv: set pmp configuration if kernel is running in M-mode

Author: torvalds

arch/riscv/boot/.gitignore

@@ -1,2 +1,4 @@
 Image
 Image.gz
+loader
+loader.lds

arch/riscv/include/asm/csr.h

@@ -72,6 +72,16 @@
 #define EXC_LOAD_PAGE_FAULT	13
 #define EXC_STORE_PAGE_FAULT	15
 
+/* PMP configuration */
+#define PMP_R			0x01
+#define PMP_W			0x02
+#define PMP_X			0x04
+#define PMP_A			0x18
+#define PMP_A_TOR		0x08
+#define PMP_A_NA4		0x10
+#define PMP_A_NAPOT		0x18
+#define PMP_L			0x80
+
 /* symbolic CSR names: */
 #define CSR_CYCLE		0xc00
 #define CSR_TIME		0xc01
@@ -100,6 +110,8 @@
 #define CSR_MCAUSE		0x342
 #define CSR_MTVAL		0x343
 #define CSR_MIP			0x344
+#define CSR_PMPCFG0		0x3a0
+#define CSR_PMPADDR0		0x3b0
 #define CSR_MHARTID		0xf14
 
 #ifdef CONFIG_RISCV_M_MODE

arch/riscv/kernel/head.S

@@ -58,6 +58,12 @@ _start_kernel:
 	/* Reset all registers except ra, a0, a1 */
 	call reset_regs
 
+	/* Setup a PMP to permit access to all of memory. */
+	li a0, -1
+	csrw CSR_PMPADDR0, a0
+	li a0, (PMP_A_NAPOT | PMP_R | PMP_W | PMP_X)
+	csrw CSR_PMPCFG0, a0
+
 	/*
 	 * The hartid in a0 is expected later on, and we have no firmware
 	 * to hand it to us.

arch/riscv/kernel/traps.c

@@ -156,6 +156,6 @@ void __init trap_init(void)
 	csr_write(CSR_SCRATCH, 0);
 	/* Set the exception vector address */
 	csr_write(CSR_TVEC, &handle_exception);
-	/* Enable all interrupts */
-	csr_write(CSR_IE, -1);
+	/* Enable interrupts */
+	csr_write(CSR_IE, IE_SIE | IE_EIE);
 }

arch/riscv/mm/kasan_init.c

@@ -19,56 +19,64 @@ asmlinkage void __init kasan_early_init(void)
 	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));
+			       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)));
+			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)));
+			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)));
+			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 i, offset;
 	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_ptes =
+	    ((n_pages + PTRS_PER_PTE) & -PTRS_PER_PTE) / PTRS_PER_PTE;
 	unsigned long n_pmds =
-		(n_pages % PTRS_PER_PTE) ? n_pages / PTRS_PER_PTE + 1 :
-						n_pages / PTRS_PER_PTE;
+	    ((n_ptes + PTRS_PER_PMD) & -PTRS_PER_PMD) / PTRS_PER_PMD;
+
+	pte_t *pte =
+	    memblock_alloc(n_ptes * PTRS_PER_PTE * sizeof(pte_t), PAGE_SIZE);
+	pmd_t *pmd =
+	    memblock_alloc(n_pmds * PTRS_PER_PMD * sizeof(pmd_t), PAGE_SIZE);
 	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));
+		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)))),
+	for (i = 0, offset = 0; i < n_ptes; i++, offset += PTRS_PER_PTE)
+		set_pmd(&pmd[i],
+			pfn_pmd(PFN_DOWN(__pa(&pte[offset])),
 				__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))),
+	for (i = 0, offset = 0; i < n_pmds; i++, offset += PTRS_PER_PMD)
+		set_pgd(&pgd[i],
+			pfn_pgd(PFN_DOWN(__pa(&pmd[offset])),
 				__pgprot(_PAGE_TABLE)));
 
 	flush_tlb_all();
@@ -81,7 +89,8 @@ void __init kasan_init(void)
 	unsigned long i;
 
 	kasan_populate_early_shadow((void *)KASAN_SHADOW_START,
-			(void *)kasan_mem_to_shadow((void *)VMALLOC_END));
+				    (void *)kasan_mem_to_shadow((void *)
+								VMALLOC_END));
 
 	for_each_memblock(memory, reg) {
 		void *start = (void *)__va(reg->base);
@@ -90,14 +99,14 @@ void __init kasan_init(void)
 		if (start >= end)
 			break;
 
-		populate(kasan_mem_to_shadow(start),
-			 kasan_mem_to_shadow(end));
+		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)));
+			       __pgprot(_PAGE_PRESENT | _PAGE_READ |
+					_PAGE_ACCESSED)));
 
 	memset(kasan_early_shadow_page, 0, PAGE_SIZE);
 	init_task.kasan_depth = 0;