Unverified Commit f7ae0233 authored by Alexandre Ghiti's avatar Alexandre Ghiti Committed by Palmer Dabbelt
Browse files

riscv: Move KASAN mapping next to the kernel mapping 



Now that KASAN_SHADOW_OFFSET is defined at compile time as a config,
this value must remain constant whatever the size of the virtual address
space, which is only possible by pushing this region at the end of the
address space next to the kernel mapping.

Signed-off-by: default avatarAlexandre Ghiti <alexandre.ghiti@canonical.com>
Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent db1503d3

Documentation/riscv/vm-layout.rst

+6 −6
Original line number Diff line number Diff line
@@ -47,12 +47,12 @@ RISC-V Linux Kernel SV39 
                                                              | Kernel-space virtual memory, shared between all processes:

  ____________________________________________________________|___________________________________________________________

                    |            |                  |         |

   ffffffc000000000 | -256    GB | ffffffc7ffffffff |   32 GB | kasan

   ffffffcefee00000 | -196    GB | ffffffcefeffffff |    2 MB | fixmap

   ffffffceff000000 | -196    GB | ffffffceffffffff |   16 MB | PCI io

   ffffffcf00000000 | -196    GB | ffffffcfffffffff |    4 GB | vmemmap

   ffffffd000000000 | -192    GB | ffffffdfffffffff |   64 GB | vmalloc/ioremap space

   ffffffe000000000 | -128    GB | ffffffff7fffffff |  124 GB | direct mapping of all physical memory

   ffffffc6fee00000 | -228    GB | ffffffc6feffffff |    2 MB | fixmap

   ffffffc6ff000000 | -228    GB | ffffffc6ffffffff |   16 MB | PCI io

   ffffffc700000000 | -228    GB | ffffffc7ffffffff |    4 GB | vmemmap

   ffffffc800000000 | -224    GB | ffffffd7ffffffff |   64 GB | vmalloc/ioremap space

   ffffffd800000000 | -160    GB | fffffff6ffffffff |  124 GB | direct mapping of all physical memory

   fffffff700000000 |  -36    GB | fffffffeffffffff |   32 GB | kasan

  __________________|____________|__________________|_________|____________________________________________________________

                                                              |

                                                              |

arch/riscv/Kconfig

+2 −2
Original line number Diff line number Diff line
@@ -160,12 +160,12 @@ config PAGE_OFFSET 
	hex

	default 0xC0000000 if 32BIT

	default 0x80000000 if 64BIT && !MMU

	default 0xffffffe000000000 if 64BIT

	default 0xffffffd800000000 if 64BIT



config KASAN_SHADOW_OFFSET

	hex

	depends on KASAN_GENERIC

	default 0xdfffffc800000000 if 64BIT

	default 0xdfffffff00000000 if 64BIT

	default 0xffffffff if 32BIT



config ARCH_FLATMEM_ENABLE

arch/riscv/include/asm/kasan.h

+2 −2
Original line number Diff line number Diff line
@@ -28,8 +28,8 @@ 
#define KASAN_SHADOW_SCALE_SHIFT	3



#define KASAN_SHADOW_SIZE	(UL(1) << ((CONFIG_VA_BITS - 1) - KASAN_SHADOW_SCALE_SHIFT))

#define KASAN_SHADOW_START	KERN_VIRT_START

#define KASAN_SHADOW_END	(KASAN_SHADOW_START + KASAN_SHADOW_SIZE)

#define KASAN_SHADOW_START	(KASAN_SHADOW_END - KASAN_SHADOW_SIZE)

#define KASAN_SHADOW_END	MODULES_LOWEST_VADDR

#define KASAN_SHADOW_OFFSET	_AC(CONFIG_KASAN_SHADOW_OFFSET, UL)



void kasan_init(void);

arch/riscv/include/asm/page.h

+0 −2
Original line number Diff line number Diff line
@@ -33,8 +33,6 @@ 
 */

#define PAGE_OFFSET		_AC(CONFIG_PAGE_OFFSET, UL)



#define KERN_VIRT_SIZE (-PAGE_OFFSET)



#ifndef __ASSEMBLY__



#define clear_page(pgaddr)			memset((pgaddr), 0, PAGE_SIZE)

arch/riscv/include/asm/pgtable.h

+15 −7
Original line number Diff line number Diff line
@@ -24,6 +24,17 @@ 
#define KERNEL_LINK_ADDR	PAGE_OFFSET

#endif



/* Number of entries in the page global directory */

#define PTRS_PER_PGD    (PAGE_SIZE / sizeof(pgd_t))

/* Number of entries in the page table */

#define PTRS_PER_PTE    (PAGE_SIZE / sizeof(pte_t))



/*

 * Half of the kernel address space (half of the entries of the page global

 * directory) is for the direct mapping.

 */

#define KERN_VIRT_SIZE          ((PTRS_PER_PGD / 2 * PGDIR_SIZE) / 2)



#define VMALLOC_SIZE     (KERN_VIRT_SIZE >> 1)

#define VMALLOC_END      (PAGE_OFFSET - 1)

#define VMALLOC_START    (PAGE_OFFSET - VMALLOC_SIZE)
@@ -39,6 +50,8 @@ 


/* Modules always live before the kernel */

#ifdef CONFIG_64BIT

/* This is used to define the end of the KASAN shadow region */

#define MODULES_LOWEST_VADDR	(KERNEL_LINK_ADDR - SZ_2G)

#define MODULES_VADDR		(PFN_ALIGN((unsigned long)&_end) - SZ_2G)

#define MODULES_END		(PFN_ALIGN((unsigned long)&_start))

#endif
@@ -108,11 +121,6 @@ 
#endif /* CONFIG_XIP_KERNEL */



#ifdef CONFIG_MMU

/* Number of entries in the page global directory */

#define PTRS_PER_PGD    (PAGE_SIZE / sizeof(pgd_t))

/* Number of entries in the page table */

#define PTRS_PER_PTE    (PAGE_SIZE / sizeof(pte_t))



/* Number of PGD entries that a user-mode program can use */

#define USER_PTRS_PER_PGD   (TASK_SIZE / PGDIR_SIZE)