[PATCH v2 0/6] RISC-V kasan rework

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* [PATCH v2 0/6] RISC-V kasan rework
@ 2023-01-23 10:09 Alexandre Ghiti
  2023-01-23 10:09 ` [PATCH v2 1/6] riscv: Split early and final KASAN population functions Alexandre Ghiti
                   ` (5 more replies)
  0 siblings, 6 replies; 10+ messages in thread
From: Alexandre Ghiti @ 2023-01-23 10:09 UTC (permalink / raw)
  To: Paul Walmsley, Palmer Dabbelt, Albert Ou, Andrey Ryabinin,
	Alexander Potapenko, Andrey Konovalov, Dmitry Vyukov,
	Vincenzo Frascino, Ard Biesheuvel, linux-riscv, linux-kernel,
	kasan-dev, linux-efi
  Cc: Alexandre Ghiti

As described in patch 2, our current kasan implementation is intricate,
so I tried to simplify the implementation and mimic what arm64/x86 are
doing.

In addition it fixes UEFI bootflow with a kasan kernel and kasan inline
instrumentation: all kasan configurations were tested on a large ubuntu
kernel with success with KASAN_KUNIT_TEST and KASAN_MODULE_TEST.

inline ubuntu config + uefi:
 sv39: OK
 sv48: OK
 sv57: OK

outline ubuntu config + uefi:
 sv39: OK
 sv48: OK
 sv57: OK

Actually 1 test always fails with KASAN_KUNIT_TEST that I have to check:
# kasan_bitops_generic: EXPECTATION FAILED at mm/kasan/kasan__test.c:1020
KASAN failure expected in "set_bit(nr, addr)", but none occurrred

Note that Palmer recently proposed to remove COMMAND_LINE_SIZE from the
userspace abi
https://lore.kernel.org/lkml/20221211061358.28035-1-palmer@rivosinc.com/T/
so that we can finally increase the command line to fit all kasan kernel
parameters.

All of this should hopefully fix the syzkaller riscv build that has been
failing for a few months now, any test is appreciated and if I can help
in any way, please ask.

v2:
- Rebase on top of v6.2-rc3
- patch 4 is now way simpler than it used to be since Ard already moved
  the string functions into the efistub.

Alexandre Ghiti (6):
  riscv: Split early and final KASAN population functions
  riscv: Rework kasan population functions
  riscv: Move DTB_EARLY_BASE_VA to the kernel address space
  riscv: Fix EFI stub usage of KASAN instrumented strcmp function
  riscv: Fix ptdump when KASAN is enabled
  riscv: Unconditionnally select KASAN_VMALLOC if KASAN

 arch/riscv/Kconfig             |   1 +
 arch/riscv/kernel/image-vars.h |   2 -
 arch/riscv/mm/init.c           |   2 +-
 arch/riscv/mm/kasan_init.c     | 516 ++++++++++++++++++---------------
 arch/riscv/mm/ptdump.c         |  24 +-
 5 files changed, 298 insertions(+), 247 deletions(-)

-- 
2.37.2

^ permalink raw reply	[flat|nested] 10+ messages in thread

* [PATCH v2 1/6] riscv: Split early and final KASAN population functions
  2023-01-23 10:09 [PATCH v2 0/6] RISC-V kasan rework Alexandre Ghiti
@ 2023-01-23 10:09 ` Alexandre Ghiti
  2023-01-23 22:15   ` Conor Dooley
  2023-01-23 10:09 ` [PATCH v2 2/6] riscv: Rework kasan " Alexandre Ghiti
                   ` (4 subsequent siblings)
  5 siblings, 1 reply; 10+ messages in thread
From: Alexandre Ghiti @ 2023-01-23 10:09 UTC (permalink / raw)
  To: Paul Walmsley, Palmer Dabbelt, Albert Ou, Andrey Ryabinin,
	Alexander Potapenko, Andrey Konovalov, Dmitry Vyukov,
	Vincenzo Frascino, Ard Biesheuvel, linux-riscv, linux-kernel,
	kasan-dev, linux-efi
  Cc: Alexandre Ghiti

This is a preliminary work that allows to make the code more
understandable.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
---
 arch/riscv/mm/kasan_init.c | 187 +++++++++++++++++++++++--------------
 1 file changed, 117 insertions(+), 70 deletions(-)

diff --git a/arch/riscv/mm/kasan_init.c b/arch/riscv/mm/kasan_init.c
index e1226709490f..9a5211ca8368 100644
--- a/arch/riscv/mm/kasan_init.c
+++ b/arch/riscv/mm/kasan_init.c
@@ -95,23 +95,13 @@ static void __init kasan_populate_pmd(pud_t *pud, unsigned long vaddr, unsigned
 }
 
 static void __init kasan_populate_pud(pgd_t *pgd,
-				      unsigned long vaddr, unsigned long end,
-				      bool early)
+				      unsigned long vaddr, unsigned long end)
 {
 	phys_addr_t phys_addr;
 	pud_t *pudp, *base_pud;
 	unsigned long next;
 
-	if (early) {
-		/*
-		 * We can't use pgd_page_vaddr here as it would return a linear
-		 * mapping address but it is not mapped yet, but when populating
-		 * early_pg_dir, we need the physical address and when populating
-		 * swapper_pg_dir, we need the kernel virtual address so use
-		 * pt_ops facility.
-		 */
-		base_pud = pt_ops.get_pud_virt(pfn_to_phys(_pgd_pfn(*pgd)));
-	} else if (pgd_none(*pgd)) {
+	if (pgd_none(*pgd)) {
 		base_pud = memblock_alloc(PTRS_PER_PUD * sizeof(pud_t), PAGE_SIZE);
 		memcpy(base_pud, (void *)kasan_early_shadow_pud,
 			sizeof(pud_t) * PTRS_PER_PUD);
@@ -130,16 +120,10 @@ static void __init kasan_populate_pud(pgd_t *pgd,
 		next = pud_addr_end(vaddr, end);
 
 		if (pud_none(*pudp) && IS_ALIGNED(vaddr, PUD_SIZE) && (next - vaddr) >= PUD_SIZE) {
-			if (early) {
-				phys_addr = __pa(((uintptr_t)kasan_early_shadow_pmd));
-				set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_TABLE));
+			phys_addr = memblock_phys_alloc(PUD_SIZE, PUD_SIZE);
+			if (phys_addr) {
+				set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_KERNEL));
 				continue;
-			} else {
-				phys_addr = memblock_phys_alloc(PUD_SIZE, PUD_SIZE);
-				if (phys_addr) {
-					set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_KERNEL));
-					continue;
-				}
 			}
 		}
 
@@ -152,35 +136,22 @@ static void __init kasan_populate_pud(pgd_t *pgd,
 	 * it entirely, memblock could allocate a page at a physical address
 	 * where KASAN is not populated yet and then we'd get a page fault.
 	 */
-	if (!early)
-		set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(base_pud)), PAGE_TABLE));
+	set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(base_pud)), PAGE_TABLE));
 }
 
 static void __init kasan_populate_p4d(pgd_t *pgd,
-				      unsigned long vaddr, unsigned long end,
-				      bool early)
+				      unsigned long vaddr, unsigned long end)
 {
 	phys_addr_t phys_addr;
 	p4d_t *p4dp, *base_p4d;
 	unsigned long next;
 
-	if (early) {
-		/*
-		 * We can't use pgd_page_vaddr here as it would return a linear
-		 * mapping address but it is not mapped yet, but when populating
-		 * early_pg_dir, we need the physical address and when populating
-		 * swapper_pg_dir, we need the kernel virtual address so use
-		 * pt_ops facility.
-		 */
-		base_p4d = pt_ops.get_p4d_virt(pfn_to_phys(_pgd_pfn(*pgd)));
-	} else {
-		base_p4d = (p4d_t *)pgd_page_vaddr(*pgd);
-		if (base_p4d == lm_alias(kasan_early_shadow_p4d)) {
-			base_p4d = memblock_alloc(PTRS_PER_PUD * sizeof(p4d_t), PAGE_SIZE);
-			memcpy(base_p4d, (void *)kasan_early_shadow_p4d,
-				sizeof(p4d_t) * PTRS_PER_P4D);
-		}
-	}
+	base_p4d = (p4d_t *)pgd_page_vaddr(*pgd);
+	if (base_p4d == lm_alias(kasan_early_shadow_p4d)) {
+		base_p4d = memblock_alloc(PTRS_PER_PUD * sizeof(p4d_t), PAGE_SIZE);
+        memcpy(base_p4d, (void *)kasan_early_shadow_p4d,
+                sizeof(p4d_t) * PTRS_PER_P4D);
+    }
 
 	p4dp = base_p4d + p4d_index(vaddr);
 
@@ -188,20 +159,14 @@ static void __init kasan_populate_p4d(pgd_t *pgd,
 		next = p4d_addr_end(vaddr, end);
 
 		if (p4d_none(*p4dp) && IS_ALIGNED(vaddr, P4D_SIZE) && (next - vaddr) >= P4D_SIZE) {
-			if (early) {
-				phys_addr = __pa(((uintptr_t)kasan_early_shadow_pud));
-				set_p4d(p4dp, pfn_p4d(PFN_DOWN(phys_addr), PAGE_TABLE));
+			phys_addr = memblock_phys_alloc(P4D_SIZE, P4D_SIZE);
+			if (phys_addr) {
+				set_p4d(p4dp, pfn_p4d(PFN_DOWN(phys_addr), PAGE_KERNEL));
 				continue;
-			} else {
-				phys_addr = memblock_phys_alloc(P4D_SIZE, P4D_SIZE);
-				if (phys_addr) {
-					set_p4d(p4dp, pfn_p4d(PFN_DOWN(phys_addr), PAGE_KERNEL));
-					continue;
-				}
 			}
 		}
 
-		kasan_populate_pud((pgd_t *)p4dp, vaddr, next, early);
+		kasan_populate_pud((pgd_t *)p4dp, vaddr, next);
 	} while (p4dp++, vaddr = next, vaddr != end);
 
 	/*
@@ -210,8 +175,7 @@ static void __init kasan_populate_p4d(pgd_t *pgd,
 	 * it entirely, memblock could allocate a page at a physical address
 	 * where KASAN is not populated yet and then we'd get a page fault.
 	 */
-	if (!early)
-		set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(base_p4d)), PAGE_TABLE));
+	set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(base_p4d)), PAGE_TABLE));
 }
 
 #define kasan_early_shadow_pgd_next			(pgtable_l5_enabled ?	\
@@ -219,16 +183,15 @@ static void __init kasan_populate_p4d(pgd_t *pgd,
 							(pgtable_l4_enabled ?	\
 				(uintptr_t)kasan_early_shadow_pud :		\
 				(uintptr_t)kasan_early_shadow_pmd))
-#define kasan_populate_pgd_next(pgdp, vaddr, next, early)			\
+#define kasan_populate_pgd_next(pgdp, vaddr, next)				\
 		(pgtable_l5_enabled ?						\
-		kasan_populate_p4d(pgdp, vaddr, next, early) :			\
+		kasan_populate_p4d(pgdp, vaddr, next) :				\
 		(pgtable_l4_enabled ?						\
-			kasan_populate_pud(pgdp, vaddr, next, early) :		\
+			kasan_populate_pud(pgdp, vaddr, next) :			\
 			kasan_populate_pmd((pud_t *)pgdp, vaddr, next)))
 
 static void __init kasan_populate_pgd(pgd_t *pgdp,
-				      unsigned long vaddr, unsigned long end,
-				      bool early)
+				      unsigned long vaddr, unsigned long end)
 {
 	phys_addr_t phys_addr;
 	unsigned long next;
@@ -237,11 +200,7 @@ static void __init kasan_populate_pgd(pgd_t *pgdp,
 		next = pgd_addr_end(vaddr, end);
 
 		if (IS_ALIGNED(vaddr, PGDIR_SIZE) && (next - vaddr) >= PGDIR_SIZE) {
-			if (early) {
-				phys_addr = __pa((uintptr_t)kasan_early_shadow_pgd_next);
-				set_pgd(pgdp, pfn_pgd(PFN_DOWN(phys_addr), PAGE_TABLE));
-				continue;
-			} else if (pgd_page_vaddr(*pgdp) ==
+			if (pgd_page_vaddr(*pgdp) ==
 				   (unsigned long)lm_alias(kasan_early_shadow_pgd_next)) {
 				/*
 				 * pgdp can't be none since kasan_early_init
@@ -258,7 +217,95 @@ static void __init kasan_populate_pgd(pgd_t *pgdp,
 			}
 		}
 
-		kasan_populate_pgd_next(pgdp, vaddr, next, early);
+		kasan_populate_pgd_next(pgdp, vaddr, next);
+	} while (pgdp++, vaddr = next, vaddr != end);
+}
+
+static void __init kasan_early_populate_pud(p4d_t *p4dp,
+					    unsigned long vaddr,
+					    unsigned long end)
+{
+	pud_t *pudp, *base_pud;
+	phys_addr_t phys_addr;
+	unsigned long next;
+
+	if (!pgtable_l4_enabled) {
+		pudp = (pud_t *)p4dp;
+	} else {
+		base_pud = pt_ops.get_pud_virt(pfn_to_phys(_p4d_pfn(*p4dp)));
+		pudp = base_pud + pud_index(vaddr);
+	}
+
+	do {
+		next = pud_addr_end(vaddr, end);
+
+		if (pud_none(*pudp) && IS_ALIGNED(vaddr, PUD_SIZE) &&
+		    (next - vaddr) >= PUD_SIZE) {
+			phys_addr = __pa((uintptr_t)kasan_early_shadow_pmd);
+			set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_TABLE));
+			continue;
+		}
+
+		BUG();
+	} while (pudp++, vaddr = next, vaddr != end);
+}
+
+static void __init kasan_early_populate_p4d(pgd_t *pgdp,
+					    unsigned long vaddr,
+					    unsigned long end)
+{
+	p4d_t *p4dp, *base_p4d;
+	phys_addr_t phys_addr;
+	unsigned long next;
+
+	/*
+	 * We can't use pgd_page_vaddr here as it would return a linear
+	 * mapping address but it is not mapped yet, but when populating
+	 * early_pg_dir, we need the physical address and when populating
+	 * swapper_pg_dir, we need the kernel virtual address so use
+	 * pt_ops facility.
+	 * Note that this test is then completely equivalent to
+	 * p4dp = p4d_offset(pgdp, vaddr)
+	 */
+	if (!pgtable_l5_enabled) {
+		p4dp = (p4d_t *)pgdp;
+	} else {
+		base_p4d = pt_ops.get_p4d_virt(pfn_to_phys(_pgd_pfn(*pgdp)));
+		p4dp = base_p4d + p4d_index(vaddr);
+	}
+
+	do {
+		next = p4d_addr_end(vaddr, end);
+
+		if (p4d_none(*p4dp) && IS_ALIGNED(vaddr, P4D_SIZE) &&
+		    (next - vaddr) >= P4D_SIZE) {
+			phys_addr = __pa((uintptr_t)kasan_early_shadow_pud);
+			set_p4d(p4dp, pfn_p4d(PFN_DOWN(phys_addr), PAGE_TABLE));
+			continue;
+		}
+
+		kasan_early_populate_pud(p4dp, vaddr, next);
+	} while (p4dp++, vaddr = next, vaddr != end);
+}
+
+static void __init kasan_early_populate_pgd(pgd_t *pgdp,
+					    unsigned long vaddr,
+					    unsigned long end)
+{
+	phys_addr_t phys_addr;
+	unsigned long next;
+
+	do {
+		next = pgd_addr_end(vaddr, end);
+
+		if (pgd_none(*pgdp) && IS_ALIGNED(vaddr, PGDIR_SIZE) &&
+		    (next - vaddr) >= PGDIR_SIZE) {
+			phys_addr = __pa((uintptr_t)kasan_early_shadow_p4d);
+			set_pgd(pgdp, pfn_pgd(PFN_DOWN(phys_addr), PAGE_TABLE));
+			continue;
+		}
+
+		kasan_early_populate_p4d(pgdp, vaddr, next);
 	} while (pgdp++, vaddr = next, vaddr != end);
 }
 
@@ -295,16 +342,16 @@ asmlinkage void __init kasan_early_init(void)
 					PAGE_TABLE));
 	}
 
-	kasan_populate_pgd(early_pg_dir + pgd_index(KASAN_SHADOW_START),
-			   KASAN_SHADOW_START, KASAN_SHADOW_END, true);
+	kasan_early_populate_pgd(early_pg_dir + pgd_index(KASAN_SHADOW_START),
+				 KASAN_SHADOW_START, KASAN_SHADOW_END);
 
 	local_flush_tlb_all();
 }
 
 void __init kasan_swapper_init(void)
 {
-	kasan_populate_pgd(pgd_offset_k(KASAN_SHADOW_START),
-			   KASAN_SHADOW_START, KASAN_SHADOW_END, true);
+	kasan_early_populate_pgd(pgd_offset_k(KASAN_SHADOW_START),
+				 KASAN_SHADOW_START, KASAN_SHADOW_END);
 
 	local_flush_tlb_all();
 }
@@ -314,7 +361,7 @@ static void __init kasan_populate(void *start, void *end)
 	unsigned long vaddr = (unsigned long)start & PAGE_MASK;
 	unsigned long vend = PAGE_ALIGN((unsigned long)end);
 
-	kasan_populate_pgd(pgd_offset_k(vaddr), vaddr, vend, false);
+	kasan_populate_pgd(pgd_offset_k(vaddr), vaddr, vend);
 
 	local_flush_tlb_all();
 	memset(start, KASAN_SHADOW_INIT, end - start);
-- 
2.37.2


^ permalink raw reply related	[flat|nested] 10+ messages in thread

* Re: [PATCH v2 1/6] riscv: Split early and final KASAN population functions
  2023-01-23 10:09 ` [PATCH v2 1/6] riscv: Split early and final KASAN population functions Alexandre Ghiti
@ 2023-01-23 22:15   ` Conor Dooley
  2023-01-24  8:00     ` Alexandre Ghiti
  0 siblings, 1 reply; 10+ messages in thread
From: Conor Dooley @ 2023-01-23 22:15 UTC (permalink / raw)
  To: Alexandre Ghiti
  Cc: Paul Walmsley, Palmer Dabbelt, Albert Ou, Andrey Ryabinin,
	Alexander Potapenko, Andrey Konovalov, Dmitry Vyukov,
	Vincenzo Frascino, Ard Biesheuvel, linux-riscv, linux-kernel,
	kasan-dev, linux-efi

[-- Attachment #1: Type: text/plain, Size: 1428 bytes --]

Hey Alex,

FYI this patch has a couple places with spaces used rather than tabs for
indent.

>  static void __init kasan_populate_p4d(pgd_t *pgd,
> -				      unsigned long vaddr, unsigned long end,
> -				      bool early)
> +				      unsigned long vaddr, unsigned long end)
>  {
>  	phys_addr_t phys_addr;
>  	p4d_t *p4dp, *base_p4d;
>  	unsigned long next;
>  
> -	if (early) {
> -		/*
> -		 * We can't use pgd_page_vaddr here as it would return a linear
> -		 * mapping address but it is not mapped yet, but when populating
> -		 * early_pg_dir, we need the physical address and when populating
> -		 * swapper_pg_dir, we need the kernel virtual address so use
> -		 * pt_ops facility.
> -		 */
> -		base_p4d = pt_ops.get_p4d_virt(pfn_to_phys(_pgd_pfn(*pgd)));
> -	} else {
> -		base_p4d = (p4d_t *)pgd_page_vaddr(*pgd);
> -		if (base_p4d == lm_alias(kasan_early_shadow_p4d)) {
> -			base_p4d = memblock_alloc(PTRS_PER_PUD * sizeof(p4d_t), PAGE_SIZE);
> -			memcpy(base_p4d, (void *)kasan_early_shadow_p4d,
> -				sizeof(p4d_t) * PTRS_PER_P4D);
> -		}
> -	}
> +	base_p4d = (p4d_t *)pgd_page_vaddr(*pgd);
> +	if (base_p4d == lm_alias(kasan_early_shadow_p4d)) {
> +		base_p4d = memblock_alloc(PTRS_PER_PUD * sizeof(p4d_t), PAGE_SIZE);
> +        memcpy(base_p4d, (void *)kasan_early_shadow_p4d,
> +                sizeof(p4d_t) * PTRS_PER_P4D);
> +    }

^^  here.

Thanks,
Conor.


[-- Attachment #2: signature.asc --]
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^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [PATCH v2 1/6] riscv: Split early and final KASAN population functions
  2023-01-23 22:15   ` Conor Dooley
@ 2023-01-24  8:00     ` Alexandre Ghiti
  0 siblings, 0 replies; 10+ messages in thread
From: Alexandre Ghiti @ 2023-01-24  8:00 UTC (permalink / raw)
  To: Conor Dooley
  Cc: Paul Walmsley, Palmer Dabbelt, Albert Ou, Andrey Ryabinin,
	Alexander Potapenko, Andrey Konovalov, Dmitry Vyukov,
	Vincenzo Frascino, Ard Biesheuvel, linux-riscv, linux-kernel,
	kasan-dev, linux-efi

Hi Conor,

On Mon, Jan 23, 2023 at 11:15 PM Conor Dooley <conor@kernel.org> wrote:
>
> Hey Alex,
>
> FYI this patch has a couple places with spaces used rather than tabs for
> indent.

Damn, I forgot to run checkpatch this time...

Thanks,

Alex

>
> >  static void __init kasan_populate_p4d(pgd_t *pgd,
> > -                                   unsigned long vaddr, unsigned long end,
> > -                                   bool early)
> > +                                   unsigned long vaddr, unsigned long end)
> >  {
> >       phys_addr_t phys_addr;
> >       p4d_t *p4dp, *base_p4d;
> >       unsigned long next;
> >
> > -     if (early) {
> > -             /*
> > -              * We can't use pgd_page_vaddr here as it would return a linear
> > -              * mapping address but it is not mapped yet, but when populating
> > -              * early_pg_dir, we need the physical address and when populating
> > -              * swapper_pg_dir, we need the kernel virtual address so use
> > -              * pt_ops facility.
> > -              */
> > -             base_p4d = pt_ops.get_p4d_virt(pfn_to_phys(_pgd_pfn(*pgd)));
> > -     } else {
> > -             base_p4d = (p4d_t *)pgd_page_vaddr(*pgd);
> > -             if (base_p4d == lm_alias(kasan_early_shadow_p4d)) {
> > -                     base_p4d = memblock_alloc(PTRS_PER_PUD * sizeof(p4d_t), PAGE_SIZE);
> > -                     memcpy(base_p4d, (void *)kasan_early_shadow_p4d,
> > -                             sizeof(p4d_t) * PTRS_PER_P4D);
> > -             }
> > -     }
> > +     base_p4d = (p4d_t *)pgd_page_vaddr(*pgd);
> > +     if (base_p4d == lm_alias(kasan_early_shadow_p4d)) {
> > +             base_p4d = memblock_alloc(PTRS_PER_PUD * sizeof(p4d_t), PAGE_SIZE);
> > +        memcpy(base_p4d, (void *)kasan_early_shadow_p4d,
> > +                sizeof(p4d_t) * PTRS_PER_P4D);
> > +    }
>
> ^^  here.
>
> Thanks,
> Conor.
>

^ permalink raw reply	[flat|nested] 10+ messages in thread

* [PATCH v2 2/6] riscv: Rework kasan population functions
  2023-01-23 10:09 [PATCH v2 0/6] RISC-V kasan rework Alexandre Ghiti
  2023-01-23 10:09 ` [PATCH v2 1/6] riscv: Split early and final KASAN population functions Alexandre Ghiti
@ 2023-01-23 10:09 ` Alexandre Ghiti
  2023-01-23 10:09 ` [PATCH v2 3/6] riscv: Move DTB_EARLY_BASE_VA to the kernel address space Alexandre Ghiti
                   ` (3 subsequent siblings)
  5 siblings, 0 replies; 10+ messages in thread
From: Alexandre Ghiti @ 2023-01-23 10:09 UTC (permalink / raw)
  To: Paul Walmsley, Palmer Dabbelt, Albert Ou, Andrey Ryabinin,
	Alexander Potapenko, Andrey Konovalov, Dmitry Vyukov,
	Vincenzo Frascino, Ard Biesheuvel, linux-riscv, linux-kernel,
	kasan-dev, linux-efi
  Cc: Alexandre Ghiti

Our previous kasan population implementation used to have the final kasan
shadow region mapped with kasan_early_shadow_page, because we did not clean
the early mapping and then we had to populate the kasan region "in-place"
which made the code cumbersome.

So now we clear the early mapping, establish a temporary mapping while we
populate the kasan shadow region with just the kernel regions that will
be used.

This new version uses the "generic" way of going through a page table
that may be folded at runtime (avoid the XXX_next macros).

It was tested with outline instrumentation on an Ubuntu kernel
configuration successfully.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
---
 arch/riscv/mm/kasan_init.c | 363 +++++++++++++++++++------------------
 1 file changed, 184 insertions(+), 179 deletions(-)

diff --git a/arch/riscv/mm/kasan_init.c b/arch/riscv/mm/kasan_init.c
index 9a5211ca8368..5c7b1d07faf2 100644
--- a/arch/riscv/mm/kasan_init.c
+++ b/arch/riscv/mm/kasan_init.c
@@ -18,58 +18,48 @@
  * For sv39, the region is aligned on PGDIR_SIZE so we only need to populate
  * the page global directory with kasan_early_shadow_pmd.
  *
- * For sv48 and sv57, the region is not aligned on PGDIR_SIZE so the mapping
- * must be divided as follows:
- * - the first PGD entry, although incomplete, is populated with
- *   kasan_early_shadow_pud/p4d
- * - the PGD entries in the middle are populated with kasan_early_shadow_pud/p4d
- * - the last PGD entry is shared with the kernel mapping so populated at the
- *   lower levels pud/p4d
- *
- * In addition, when shallow populating a kasan region (for example vmalloc),
- * this region may also not be aligned on PGDIR size, so we must go down to the
- * pud level too.
+ * For sv48 and sv57, the region start is aligned on PGDIR_SIZE whereas the end
+ * region is not and then we have to go down to the PUD level.
  */
 
 extern pgd_t early_pg_dir[PTRS_PER_PGD];
+pgd_t tmp_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
+p4d_t tmp_p4d[PTRS_PER_P4D] __page_aligned_bss;
+pud_t tmp_pud[PTRS_PER_PUD] __page_aligned_bss;
 
 static void __init kasan_populate_pte(pmd_t *pmd, unsigned long vaddr, unsigned long end)
 {
 	phys_addr_t phys_addr;
-	pte_t *ptep, *base_pte;
+	pte_t *ptep, *p;
 
-	if (pmd_none(*pmd))
-		base_pte = memblock_alloc(PTRS_PER_PTE * sizeof(pte_t), PAGE_SIZE);
-	else
-		base_pte = (pte_t *)pmd_page_vaddr(*pmd);
+	if (pmd_none(*pmd)) {
+		p = memblock_alloc(PTRS_PER_PTE * sizeof(pte_t), PAGE_SIZE);
+		set_pmd(pmd, pfn_pmd(PFN_DOWN(__pa(p)), PAGE_TABLE));
+	}
 
-	ptep = base_pte + pte_index(vaddr);
+	ptep = pte_offset_kernel(pmd, vaddr);
 
 	do {
 		if (pte_none(*ptep)) {
 			phys_addr = memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
 			set_pte(ptep, pfn_pte(PFN_DOWN(phys_addr), PAGE_KERNEL));
+			memset(__va(phys_addr), KASAN_SHADOW_INIT, PAGE_SIZE);
 		}
 	} while (ptep++, vaddr += PAGE_SIZE, vaddr != end);
-
-	set_pmd(pmd, pfn_pmd(PFN_DOWN(__pa(base_pte)), PAGE_TABLE));
 }
 
 static void __init kasan_populate_pmd(pud_t *pud, unsigned long vaddr, unsigned long end)
 {
 	phys_addr_t phys_addr;
-	pmd_t *pmdp, *base_pmd;
+	pmd_t *pmdp, *p;
 	unsigned long next;
 
 	if (pud_none(*pud)) {
-		base_pmd = memblock_alloc(PTRS_PER_PMD * sizeof(pmd_t), PAGE_SIZE);
-	} else {
-		base_pmd = (pmd_t *)pud_pgtable(*pud);
-		if (base_pmd == lm_alias(kasan_early_shadow_pmd))
-			base_pmd = memblock_alloc(PTRS_PER_PMD * sizeof(pmd_t), PAGE_SIZE);
+		p = memblock_alloc(PTRS_PER_PMD * sizeof(pmd_t), PAGE_SIZE);
+		set_pud(pud, pfn_pud(PFN_DOWN(__pa(p)), PAGE_TABLE));
 	}
 
-	pmdp = base_pmd + pmd_index(vaddr);
+	pmdp = pmd_offset(pud, vaddr);
 
 	do {
 		next = pmd_addr_end(vaddr, end);
@@ -78,43 +68,28 @@ static void __init kasan_populate_pmd(pud_t *pud, unsigned long vaddr, unsigned
 			phys_addr = memblock_phys_alloc(PMD_SIZE, PMD_SIZE);
 			if (phys_addr) {
 				set_pmd(pmdp, pfn_pmd(PFN_DOWN(phys_addr), PAGE_KERNEL));
+				memset(__va(phys_addr), KASAN_SHADOW_INIT, PMD_SIZE);
 				continue;
 			}
 		}
 
 		kasan_populate_pte(pmdp, vaddr, next);
 	} while (pmdp++, vaddr = next, vaddr != end);
-
-	/*
-	 * Wait for the whole PGD to be populated before setting the PGD in
-	 * the page table, otherwise, if we did set the PGD before populating
-	 * it entirely, memblock could allocate a page at a physical address
-	 * where KASAN is not populated yet and then we'd get a page fault.
-	 */
-	set_pud(pud, pfn_pud(PFN_DOWN(__pa(base_pmd)), PAGE_TABLE));
 }
 
-static void __init kasan_populate_pud(pgd_t *pgd,
+static void __init kasan_populate_pud(p4d_t *p4d,
 				      unsigned long vaddr, unsigned long end)
 {
 	phys_addr_t phys_addr;
-	pud_t *pudp, *base_pud;
+	pud_t *pudp, *p;
 	unsigned long next;
 
-	if (pgd_none(*pgd)) {
-		base_pud = memblock_alloc(PTRS_PER_PUD * sizeof(pud_t), PAGE_SIZE);
-		memcpy(base_pud, (void *)kasan_early_shadow_pud,
-			sizeof(pud_t) * PTRS_PER_PUD);
-	} else {
-		base_pud = (pud_t *)pgd_page_vaddr(*pgd);
-		if (base_pud == lm_alias(kasan_early_shadow_pud)) {
-			base_pud = memblock_alloc(PTRS_PER_PUD * sizeof(pud_t), PAGE_SIZE);
-			memcpy(base_pud, (void *)kasan_early_shadow_pud,
-			       sizeof(pud_t) * PTRS_PER_PUD);
-		}
+	if (p4d_none(*p4d)) {
+		p = memblock_alloc(PTRS_PER_PUD * sizeof(pud_t), PAGE_SIZE);
+		set_p4d(p4d, pfn_p4d(PFN_DOWN(__pa(p)), PAGE_TABLE));
 	}
 
-	pudp = base_pud + pud_index(vaddr);
+	pudp = pud_offset(p4d, vaddr);
 
 	do {
 		next = pud_addr_end(vaddr, end);
@@ -123,37 +98,28 @@ static void __init kasan_populate_pud(pgd_t *pgd,
 			phys_addr = memblock_phys_alloc(PUD_SIZE, PUD_SIZE);
 			if (phys_addr) {
 				set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_KERNEL));
+				memset(__va(phys_addr), KASAN_SHADOW_INIT, PUD_SIZE);
 				continue;
 			}
 		}
 
 		kasan_populate_pmd(pudp, vaddr, next);
 	} while (pudp++, vaddr = next, vaddr != end);
-
-	/*
-	 * Wait for the whole PGD to be populated before setting the PGD in
-	 * the page table, otherwise, if we did set the PGD before populating
-	 * it entirely, memblock could allocate a page at a physical address
-	 * where KASAN is not populated yet and then we'd get a page fault.
-	 */
-	set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(base_pud)), PAGE_TABLE));
 }
 
 static void __init kasan_populate_p4d(pgd_t *pgd,
 				      unsigned long vaddr, unsigned long end)
 {
 	phys_addr_t phys_addr;
-	p4d_t *p4dp, *base_p4d;
+	p4d_t *p4dp, *p;
 	unsigned long next;
 
-	base_p4d = (p4d_t *)pgd_page_vaddr(*pgd);
-	if (base_p4d == lm_alias(kasan_early_shadow_p4d)) {
-		base_p4d = memblock_alloc(PTRS_PER_PUD * sizeof(p4d_t), PAGE_SIZE);
-        memcpy(base_p4d, (void *)kasan_early_shadow_p4d,
-                sizeof(p4d_t) * PTRS_PER_P4D);
-    }
+	if (pgd_none(*pgd)) {
+		p = memblock_alloc(PTRS_PER_P4D * sizeof(p4d_t), PAGE_SIZE);
+		set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(p)), PAGE_TABLE));
+	}
 
-	p4dp = base_p4d + p4d_index(vaddr);
+	p4dp = p4d_offset(pgd, vaddr);
 
 	do {
 		next = p4d_addr_end(vaddr, end);
@@ -162,34 +128,15 @@ static void __init kasan_populate_p4d(pgd_t *pgd,
 			phys_addr = memblock_phys_alloc(P4D_SIZE, P4D_SIZE);
 			if (phys_addr) {
 				set_p4d(p4dp, pfn_p4d(PFN_DOWN(phys_addr), PAGE_KERNEL));
+				memset(__va(phys_addr), KASAN_SHADOW_INIT, P4D_SIZE);
 				continue;
 			}
 		}
 
-		kasan_populate_pud((pgd_t *)p4dp, vaddr, next);
+		kasan_populate_pud(p4dp, vaddr, next);
 	} while (p4dp++, vaddr = next, vaddr != end);
-
-	/*
-	 * Wait for the whole P4D to be populated before setting the P4D in
-	 * the page table, otherwise, if we did set the P4D before populating
-	 * it entirely, memblock could allocate a page at a physical address
-	 * where KASAN is not populated yet and then we'd get a page fault.
-	 */
-	set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(base_p4d)), PAGE_TABLE));
 }
 
-#define kasan_early_shadow_pgd_next			(pgtable_l5_enabled ?	\
-				(uintptr_t)kasan_early_shadow_p4d :		\
-							(pgtable_l4_enabled ?	\
-				(uintptr_t)kasan_early_shadow_pud :		\
-				(uintptr_t)kasan_early_shadow_pmd))
-#define kasan_populate_pgd_next(pgdp, vaddr, next)				\
-		(pgtable_l5_enabled ?						\
-		kasan_populate_p4d(pgdp, vaddr, next) :				\
-		(pgtable_l4_enabled ?						\
-			kasan_populate_pud(pgdp, vaddr, next) :			\
-			kasan_populate_pmd((pud_t *)pgdp, vaddr, next)))
-
 static void __init kasan_populate_pgd(pgd_t *pgdp,
 				      unsigned long vaddr, unsigned long end)
 {
@@ -199,25 +146,86 @@ static void __init kasan_populate_pgd(pgd_t *pgdp,
 	do {
 		next = pgd_addr_end(vaddr, end);
 
-		if (IS_ALIGNED(vaddr, PGDIR_SIZE) && (next - vaddr) >= PGDIR_SIZE) {
-			if (pgd_page_vaddr(*pgdp) ==
-				   (unsigned long)lm_alias(kasan_early_shadow_pgd_next)) {
-				/*
-				 * pgdp can't be none since kasan_early_init
-				 * initialized all KASAN shadow region with
-				 * kasan_early_shadow_pud: if this is still the
-				 * case, that means we can try to allocate a
-				 * hugepage as a replacement.
-				 */
-				phys_addr = memblock_phys_alloc(PGDIR_SIZE, PGDIR_SIZE);
-				if (phys_addr) {
-					set_pgd(pgdp, pfn_pgd(PFN_DOWN(phys_addr), PAGE_KERNEL));
-					continue;
-				}
+		if (pgd_none(*pgdp) && IS_ALIGNED(vaddr, PGDIR_SIZE) &&
+		    (next - vaddr) >= PGDIR_SIZE) {
+			phys_addr = memblock_phys_alloc(PGDIR_SIZE, PGDIR_SIZE);
+			if (phys_addr) {
+				set_pgd(pgdp, pfn_pgd(PFN_DOWN(phys_addr), PAGE_KERNEL));
+				memset(__va(phys_addr), KASAN_SHADOW_INIT, PGDIR_SIZE);
+				continue;
 			}
 		}
 
-		kasan_populate_pgd_next(pgdp, vaddr, next);
+		kasan_populate_p4d(pgdp, vaddr, next);
+	} while (pgdp++, vaddr = next, vaddr != end);
+}
+
+static void __init kasan_early_clear_pud(p4d_t *p4dp,
+					 unsigned long vaddr, unsigned long end)
+{
+	pud_t *pudp, *base_pud;
+	unsigned long next;
+
+	if (!pgtable_l4_enabled) {
+		pudp = (pud_t *)p4dp;
+	} else {
+		base_pud = pt_ops.get_pud_virt(pfn_to_phys(_p4d_pfn(*p4dp)));
+		pudp = base_pud + pud_index(vaddr);
+	}
+
+	do {
+		next = pud_addr_end(vaddr, end);
+
+		if (IS_ALIGNED(vaddr, PUD_SIZE) && (next - vaddr) >= PUD_SIZE) {
+			pud_clear(pudp);
+			continue;
+		}
+
+		BUG();
+	} while (pudp++, vaddr = next, vaddr != end);
+}
+
+static void __init kasan_early_clear_p4d(pgd_t *pgdp,
+					 unsigned long vaddr, unsigned long end)
+{
+	p4d_t *p4dp, *base_p4d;
+	unsigned long next;
+
+	if (!pgtable_l5_enabled) {
+		p4dp = (p4d_t *)pgdp;
+	} else {
+		base_p4d = pt_ops.get_p4d_virt(pfn_to_phys(_pgd_pfn(*pgdp)));
+		p4dp = base_p4d + p4d_index(vaddr);
+	}
+
+	do {
+		next = p4d_addr_end(vaddr, end);
+
+		if (pgtable_l4_enabled && IS_ALIGNED(vaddr, P4D_SIZE) &&
+		    (next - vaddr) >= P4D_SIZE) {
+			p4d_clear(p4dp);
+			continue;
+		}
+
+		kasan_early_clear_pud(p4dp, vaddr, next);
+	} while (p4dp++, vaddr = next, vaddr != end);
+}
+
+static void __init kasan_early_clear_pgd(pgd_t *pgdp,
+					 unsigned long vaddr, unsigned long end)
+{
+	unsigned long next;
+
+	do {
+		next = pgd_addr_end(vaddr, end);
+
+		if (pgtable_l5_enabled && IS_ALIGNED(vaddr, PGDIR_SIZE) &&
+		    (next - vaddr) >= PGDIR_SIZE) {
+			pgd_clear(pgdp);
+			continue;
+		}
+
+		kasan_early_clear_p4d(pgdp, vaddr, next);
 	} while (pgdp++, vaddr = next, vaddr != end);
 }
 
@@ -362,117 +370,64 @@ static void __init kasan_populate(void *start, void *end)
 	unsigned long vend = PAGE_ALIGN((unsigned long)end);
 
 	kasan_populate_pgd(pgd_offset_k(vaddr), vaddr, vend);
-
-	local_flush_tlb_all();
-	memset(start, KASAN_SHADOW_INIT, end - start);
 }
 
-static void __init kasan_shallow_populate_pmd(pgd_t *pgdp,
+static void __init kasan_shallow_populate_pud(p4d_t *p4d,
 					      unsigned long vaddr, unsigned long end)
 {
 	unsigned long next;
-	pmd_t *pmdp, *base_pmd;
-	bool is_kasan_pte;
-
-	base_pmd = (pmd_t *)pgd_page_vaddr(*pgdp);
-	pmdp = base_pmd + pmd_index(vaddr);
-
-	do {
-		next = pmd_addr_end(vaddr, end);
-		is_kasan_pte = (pmd_pgtable(*pmdp) == lm_alias(kasan_early_shadow_pte));
-
-		if (is_kasan_pte)
-			pmd_clear(pmdp);
-	} while (pmdp++, vaddr = next, vaddr != end);
-}
-
-static void __init kasan_shallow_populate_pud(pgd_t *pgdp,
-					      unsigned long vaddr, unsigned long end)
-{
-	unsigned long next;
-	pud_t *pudp, *base_pud;
-	pmd_t *base_pmd;
-	bool is_kasan_pmd;
-
-	base_pud = (pud_t *)pgd_page_vaddr(*pgdp);
-	pudp = base_pud + pud_index(vaddr);
+	void *p;
+	pud_t *pud_k = pud_offset(p4d, vaddr);
 
 	do {
 		next = pud_addr_end(vaddr, end);
-		is_kasan_pmd = (pud_pgtable(*pudp) == lm_alias(kasan_early_shadow_pmd));
 
-		if (!is_kasan_pmd)
-			continue;
-
-		base_pmd = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
-		set_pud(pudp, pfn_pud(PFN_DOWN(__pa(base_pmd)), PAGE_TABLE));
-
-		if (IS_ALIGNED(vaddr, PUD_SIZE) && (next - vaddr) >= PUD_SIZE)
+		if (pud_none(*pud_k)) {
+			p = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
+			set_pud(pud_k, pfn_pud(PFN_DOWN(__pa(p)), PAGE_TABLE));
 			continue;
+		}
 
-		memcpy(base_pmd, (void *)kasan_early_shadow_pmd, PAGE_SIZE);
-		kasan_shallow_populate_pmd((pgd_t *)pudp, vaddr, next);
-	} while (pudp++, vaddr = next, vaddr != end);
+		BUG();
+	} while (pud_k++, vaddr = next, vaddr != end);
 }
 
-static void __init kasan_shallow_populate_p4d(pgd_t *pgdp,
+static void __init kasan_shallow_populate_p4d(pgd_t *pgd,
 					      unsigned long vaddr, unsigned long end)
 {
 	unsigned long next;
-	p4d_t *p4dp, *base_p4d;
-	pud_t *base_pud;
-	bool is_kasan_pud;
-
-	base_p4d = (p4d_t *)pgd_page_vaddr(*pgdp);
-	p4dp = base_p4d + p4d_index(vaddr);
+	void *p;
+	p4d_t *p4d_k = p4d_offset(pgd, vaddr);
 
 	do {
 		next = p4d_addr_end(vaddr, end);
-		is_kasan_pud = (p4d_pgtable(*p4dp) == lm_alias(kasan_early_shadow_pud));
-
-		if (!is_kasan_pud)
-			continue;
-
-		base_pud = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
-		set_p4d(p4dp, pfn_p4d(PFN_DOWN(__pa(base_pud)), PAGE_TABLE));
 
-		if (IS_ALIGNED(vaddr, P4D_SIZE) && (next - vaddr) >= P4D_SIZE)
+		if (p4d_none(*p4d_k)) {
+			p = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
+			set_p4d(p4d_k, pfn_p4d(PFN_DOWN(__pa(p)), PAGE_TABLE));
 			continue;
+		}
 
-		memcpy(base_pud, (void *)kasan_early_shadow_pud, PAGE_SIZE);
-		kasan_shallow_populate_pud((pgd_t *)p4dp, vaddr, next);
-	} while (p4dp++, vaddr = next, vaddr != end);
+		kasan_shallow_populate_pud(p4d_k, vaddr, end);
+	} while (p4d_k++, vaddr = next, vaddr != end);
 }
 
-#define kasan_shallow_populate_pgd_next(pgdp, vaddr, next)			\
-		(pgtable_l5_enabled ?						\
-		kasan_shallow_populate_p4d(pgdp, vaddr, next) :			\
-		(pgtable_l4_enabled ?						\
-		kasan_shallow_populate_pud(pgdp, vaddr, next) :			\
-		kasan_shallow_populate_pmd(pgdp, vaddr, next)))
-
 static void __init kasan_shallow_populate_pgd(unsigned long vaddr, unsigned long end)
 {
 	unsigned long next;
 	void *p;
 	pgd_t *pgd_k = pgd_offset_k(vaddr);
-	bool is_kasan_pgd_next;
 
 	do {
 		next = pgd_addr_end(vaddr, end);
-		is_kasan_pgd_next = (pgd_page_vaddr(*pgd_k) ==
-				     (unsigned long)lm_alias(kasan_early_shadow_pgd_next));
 
-		if (is_kasan_pgd_next) {
+		if (pgd_none(*pgd_k)) {
 			p = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 			set_pgd(pgd_k, pfn_pgd(PFN_DOWN(__pa(p)), PAGE_TABLE));
-		}
-
-		if (IS_ALIGNED(vaddr, PGDIR_SIZE) && (next - vaddr) >= PGDIR_SIZE)
 			continue;
+		}
 
-		memcpy(p, (void *)kasan_early_shadow_pgd_next, PAGE_SIZE);
-		kasan_shallow_populate_pgd_next(pgd_k, vaddr, next);
+		kasan_shallow_populate_p4d(pgd_k, vaddr, next);
 	} while (pgd_k++, vaddr = next, vaddr != end);
 }
 
@@ -482,7 +437,37 @@ static void __init kasan_shallow_populate(void *start, void *end)
 	unsigned long vend = PAGE_ALIGN((unsigned long)end);
 
 	kasan_shallow_populate_pgd(vaddr, vend);
-	local_flush_tlb_all();
+}
+
+void create_tmp_mapping(void)
+{
+	void *ptr;
+	p4d_t *base_p4d;
+
+	/*
+	 * We need to clean the early mapping: this is hard to achieve "in-place",
+	 * so install a temporary mapping like arm64 and x86 do.
+	 */
+	memcpy(tmp_pg_dir, swapper_pg_dir, sizeof(pgd_t) * PTRS_PER_PGD);
+
+	/* Copy the last p4d since it is shared with the kernel mapping. */
+	if (pgtable_l5_enabled) {
+		ptr = (p4d_t *)pgd_page_vaddr(*pgd_offset_k(KASAN_SHADOW_END));
+		memcpy(tmp_p4d, ptr, sizeof(p4d_t) * PTRS_PER_P4D);
+		set_pgd(&tmp_pg_dir[pgd_index(KASAN_SHADOW_END)],
+			pfn_pgd(PFN_DOWN(__pa(tmp_p4d)), PAGE_TABLE));
+		base_p4d = tmp_p4d;
+	} else {
+		base_p4d = (p4d_t *)tmp_pg_dir;
+	}
+
+	/* Copy the last pud since it is shared with the kernel mapping. */
+	if (pgtable_l4_enabled) {
+		ptr = (pud_t *)p4d_page_vaddr(*(base_p4d + p4d_index(KASAN_SHADOW_END)));
+		memcpy(tmp_pud, ptr, sizeof(pud_t) * PTRS_PER_PUD);
+		set_p4d(&base_p4d[p4d_index(KASAN_SHADOW_END)],
+			pfn_p4d(PFN_DOWN(__pa(tmp_pud)), PAGE_TABLE));
+	}
 }
 
 void __init kasan_init(void)
@@ -490,10 +475,27 @@ void __init kasan_init(void)
 	phys_addr_t p_start, p_end;
 	u64 i;
 
-	if (IS_ENABLED(CONFIG_KASAN_VMALLOC))
+	create_tmp_mapping();
+	csr_write(CSR_SATP, PFN_DOWN(__pa(tmp_pg_dir)) | satp_mode);
+
+	kasan_early_clear_pgd(pgd_offset_k(KASAN_SHADOW_START),
+			      KASAN_SHADOW_START, KASAN_SHADOW_END);
+
+	kasan_populate_early_shadow((void *)kasan_mem_to_shadow((void *)FIXADDR_START),
+				    (void *)kasan_mem_to_shadow((void *)VMALLOC_START));
+
+	if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) {
 		kasan_shallow_populate(
 			(void *)kasan_mem_to_shadow((void *)VMALLOC_START),
 			(void *)kasan_mem_to_shadow((void *)VMALLOC_END));
+		/* Shallow populate modules and BPF which are vmalloc-allocated */
+		kasan_shallow_populate(
+			(void *)kasan_mem_to_shadow((void *)MODULES_VADDR),
+			(void *)kasan_mem_to_shadow((void *)MODULES_END));
+	} else {
+		kasan_populate_early_shadow((void *)kasan_mem_to_shadow((void *)VMALLOC_START),
+					    (void *)kasan_mem_to_shadow((void *)VMALLOC_END));
+	}
 
 	/* Populate the linear mapping */
 	for_each_mem_range(i, &p_start, &p_end) {
@@ -506,8 +508,8 @@ void __init kasan_init(void)
 		kasan_populate(kasan_mem_to_shadow(start), kasan_mem_to_shadow(end));
 	}
 
-	/* Populate kernel, BPF, modules mapping */
-	kasan_populate(kasan_mem_to_shadow((const void *)MODULES_VADDR),
+	/* Populate kernel */
+	kasan_populate(kasan_mem_to_shadow((const void *)MODULES_END),
 		       kasan_mem_to_shadow((const void *)MODULES_VADDR + SZ_2G));
 
 	for (i = 0; i < PTRS_PER_PTE; i++)
@@ -518,4 +520,7 @@ void __init kasan_init(void)
 
 	memset(kasan_early_shadow_page, KASAN_SHADOW_INIT, PAGE_SIZE);
 	init_task.kasan_depth = 0;
+
+	csr_write(CSR_SATP, PFN_DOWN(__pa(swapper_pg_dir)) | satp_mode);
+	local_flush_tlb_all();
 }
-- 
2.37.2


^ permalink raw reply related	[flat|nested] 10+ messages in thread

* [PATCH v2 3/6] riscv: Move DTB_EARLY_BASE_VA to the kernel address space
  2023-01-23 10:09 [PATCH v2 0/6] RISC-V kasan rework Alexandre Ghiti
  2023-01-23 10:09 ` [PATCH v2 1/6] riscv: Split early and final KASAN population functions Alexandre Ghiti
  2023-01-23 10:09 ` [PATCH v2 2/6] riscv: Rework kasan " Alexandre Ghiti
@ 2023-01-23 10:09 ` Alexandre Ghiti
  2023-01-23 10:09 ` [PATCH v2 4/6] riscv: Fix EFI stub usage of KASAN instrumented strcmp function Alexandre Ghiti
                   ` (2 subsequent siblings)
  5 siblings, 0 replies; 10+ messages in thread
From: Alexandre Ghiti @ 2023-01-23 10:09 UTC (permalink / raw)
  To: Paul Walmsley, Palmer Dabbelt, Albert Ou, Andrey Ryabinin,
	Alexander Potapenko, Andrey Konovalov, Dmitry Vyukov,
	Vincenzo Frascino, Ard Biesheuvel, linux-riscv, linux-kernel,
	kasan-dev, linux-efi
  Cc: Alexandre Ghiti

The early virtual address should lie in the kernel address space for
inline kasan instrumentation to succeed, otherwise kasan tries to
dereference an address that does not exist in the address space (since
kasan only maps *kernel* address space, not the userspace).

Simply use the very first address of the kernel address space for the
early fdt mapping.

It allowed an Ubuntu kernel to boot successfully with inline
instrumentation.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
---
 arch/riscv/mm/init.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 478d6763a01a..87f6a5d475a6 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -57,7 +57,7 @@ unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]
 EXPORT_SYMBOL(empty_zero_page);
 
 extern char _start[];
-#define DTB_EARLY_BASE_VA      PGDIR_SIZE
+#define DTB_EARLY_BASE_VA      (ADDRESS_SPACE_END - (PTRS_PER_PGD / 2 * PGDIR_SIZE) + 1)
 void *_dtb_early_va __initdata;
 uintptr_t _dtb_early_pa __initdata;
 
-- 
2.37.2


^ permalink raw reply related	[flat|nested] 10+ messages in thread

* [PATCH v2 4/6] riscv: Fix EFI stub usage of KASAN instrumented strcmp function
  2023-01-23 10:09 [PATCH v2 0/6] RISC-V kasan rework Alexandre Ghiti
                   ` (2 preceding siblings ...)
  2023-01-23 10:09 ` [PATCH v2 3/6] riscv: Move DTB_EARLY_BASE_VA to the kernel address space Alexandre Ghiti
@ 2023-01-23 10:09 ` Alexandre Ghiti
  2023-01-23 10:19   ` Ard Biesheuvel
  2023-01-23 10:09 ` [PATCH v2 5/6] riscv: Fix ptdump when KASAN is enabled Alexandre Ghiti
  2023-01-23 10:09 ` [PATCH v2 6/6] riscv: Unconditionnally select KASAN_VMALLOC if KASAN Alexandre Ghiti
  5 siblings, 1 reply; 10+ messages in thread
From: Alexandre Ghiti @ 2023-01-23 10:09 UTC (permalink / raw)
  To: Paul Walmsley, Palmer Dabbelt, Albert Ou, Andrey Ryabinin,
	Alexander Potapenko, Andrey Konovalov, Dmitry Vyukov,
	Vincenzo Frascino, Ard Biesheuvel, linux-riscv, linux-kernel,
	kasan-dev, linux-efi
  Cc: Alexandre Ghiti, Alexandre Ghiti

From: Alexandre Ghiti <alexghiti@alexghiti.eu.rivosinc.com>

The EFI stub must not use any KASAN instrumented code as the kernel
proper did not initialize the thread pointer and the mapping for the
KASAN shadow region.

Avoid using the generic strcmp function, instead use the one in
drivers/firmware/efi/libstub/string.c.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
---
 arch/riscv/kernel/image-vars.h | 2 --
 1 file changed, 2 deletions(-)

diff --git a/arch/riscv/kernel/image-vars.h b/arch/riscv/kernel/image-vars.h
index 7e2962ef73f9..15616155008c 100644
--- a/arch/riscv/kernel/image-vars.h
+++ b/arch/riscv/kernel/image-vars.h
@@ -23,8 +23,6 @@
  * linked at. The routines below are all implemented in assembler in a
  * position independent manner
  */
-__efistub_strcmp		= strcmp;
-
 __efistub__start		= _start;
 __efistub__start_kernel		= _start_kernel;
 __efistub__end			= _end;
-- 
2.37.2


^ permalink raw reply related	[flat|nested] 10+ messages in thread

* Re: [PATCH v2 4/6] riscv: Fix EFI stub usage of KASAN instrumented strcmp function
  2023-01-23 10:09 ` [PATCH v2 4/6] riscv: Fix EFI stub usage of KASAN instrumented strcmp function Alexandre Ghiti
@ 2023-01-23 10:19   ` Ard Biesheuvel
  0 siblings, 0 replies; 10+ messages in thread
From: Ard Biesheuvel @ 2023-01-23 10:19 UTC (permalink / raw)
  To: Alexandre Ghiti
  Cc: Paul Walmsley, Palmer Dabbelt, Albert Ou, Andrey Ryabinin,
	Alexander Potapenko, Andrey Konovalov, Dmitry Vyukov,
	Vincenzo Frascino, linux-riscv, linux-kernel, kasan-dev,
	linux-efi, Alexandre Ghiti

On Mon, 23 Jan 2023 at 11:14, Alexandre Ghiti <alexghiti@rivosinc.com> wrote:
>
> From: Alexandre Ghiti <alexghiti@alexghiti.eu.rivosinc.com>
>
> The EFI stub must not use any KASAN instrumented code as the kernel
> proper did not initialize the thread pointer and the mapping for the
> KASAN shadow region.
>
> Avoid using the generic strcmp function, instead use the one in
> drivers/firmware/efi/libstub/string.c.
>
> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>

Acked-by: Ard Biesheuvel <ardb@kernel.org>

> ---
>  arch/riscv/kernel/image-vars.h | 2 --
>  1 file changed, 2 deletions(-)
>
> diff --git a/arch/riscv/kernel/image-vars.h b/arch/riscv/kernel/image-vars.h
> index 7e2962ef73f9..15616155008c 100644
> --- a/arch/riscv/kernel/image-vars.h
> +++ b/arch/riscv/kernel/image-vars.h
> @@ -23,8 +23,6 @@
>   * linked at. The routines below are all implemented in assembler in a
>   * position independent manner
>   */
> -__efistub_strcmp               = strcmp;
> -
>  __efistub__start               = _start;
>  __efistub__start_kernel                = _start_kernel;
>  __efistub__end                 = _end;
> --
> 2.37.2
>

^ permalink raw reply	[flat|nested] 10+ messages in thread

* [PATCH v2 5/6] riscv: Fix ptdump when KASAN is enabled
  2023-01-23 10:09 [PATCH v2 0/6] RISC-V kasan rework Alexandre Ghiti
                   ` (3 preceding siblings ...)
  2023-01-23 10:09 ` [PATCH v2 4/6] riscv: Fix EFI stub usage of KASAN instrumented strcmp function Alexandre Ghiti
@ 2023-01-23 10:09 ` Alexandre Ghiti
  2023-01-23 10:09 ` [PATCH v2 6/6] riscv: Unconditionnally select KASAN_VMALLOC if KASAN Alexandre Ghiti
  5 siblings, 0 replies; 10+ messages in thread
From: Alexandre Ghiti @ 2023-01-23 10:09 UTC (permalink / raw)
  To: Paul Walmsley, Palmer Dabbelt, Albert Ou, Andrey Ryabinin,
	Alexander Potapenko, Andrey Konovalov, Dmitry Vyukov,
	Vincenzo Frascino, Ard Biesheuvel, linux-riscv, linux-kernel,
	kasan-dev, linux-efi
  Cc: Alexandre Ghiti

The KASAN shadow region was moved next to the kernel mapping but the
ptdump code was not updated and it appears to break the dump of the kernel
page table, so fix this by moving the KASAN shadow region in ptdump.

Fixes: f7ae02333d13 ("riscv: Move KASAN mapping next to the kernel mapping")
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
---
 arch/riscv/mm/ptdump.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/arch/riscv/mm/ptdump.c b/arch/riscv/mm/ptdump.c
index 830e7de65e3a..20a9f991a6d7 100644
--- a/arch/riscv/mm/ptdump.c
+++ b/arch/riscv/mm/ptdump.c
@@ -59,10 +59,6 @@ struct ptd_mm_info {
 };
 
 enum address_markers_idx {
-#ifdef CONFIG_KASAN
-	KASAN_SHADOW_START_NR,
-	KASAN_SHADOW_END_NR,
-#endif
 	FIXMAP_START_NR,
 	FIXMAP_END_NR,
 	PCI_IO_START_NR,
@@ -74,6 +70,10 @@ enum address_markers_idx {
 	VMALLOC_START_NR,
 	VMALLOC_END_NR,
 	PAGE_OFFSET_NR,
+#ifdef CONFIG_KASAN
+	KASAN_SHADOW_START_NR,
+	KASAN_SHADOW_END_NR,
+#endif
 #ifdef CONFIG_64BIT
 	MODULES_MAPPING_NR,
 	KERNEL_MAPPING_NR,
@@ -82,10 +82,6 @@ enum address_markers_idx {
 };
 
 static struct addr_marker address_markers[] = {
-#ifdef CONFIG_KASAN
-	{0, "Kasan shadow start"},
-	{0, "Kasan shadow end"},
-#endif
 	{0, "Fixmap start"},
 	{0, "Fixmap end"},
 	{0, "PCI I/O start"},
@@ -97,6 +93,10 @@ static struct addr_marker address_markers[] = {
 	{0, "vmalloc() area"},
 	{0, "vmalloc() end"},
 	{0, "Linear mapping"},
+#ifdef CONFIG_KASAN
+	{0, "Kasan shadow start"},
+	{0, "Kasan shadow end"},
+#endif
 #ifdef CONFIG_64BIT
 	{0, "Modules/BPF mapping"},
 	{0, "Kernel mapping"},
@@ -362,10 +362,6 @@ static int __init ptdump_init(void)
 {
 	unsigned int i, j;
 
-#ifdef CONFIG_KASAN
-	address_markers[KASAN_SHADOW_START_NR].start_address = KASAN_SHADOW_START;
-	address_markers[KASAN_SHADOW_END_NR].start_address = KASAN_SHADOW_END;
-#endif
 	address_markers[FIXMAP_START_NR].start_address = FIXADDR_START;
 	address_markers[FIXMAP_END_NR].start_address = FIXADDR_TOP;
 	address_markers[PCI_IO_START_NR].start_address = PCI_IO_START;
@@ -377,6 +373,10 @@ static int __init ptdump_init(void)
 	address_markers[VMALLOC_START_NR].start_address = VMALLOC_START;
 	address_markers[VMALLOC_END_NR].start_address = VMALLOC_END;
 	address_markers[PAGE_OFFSET_NR].start_address = PAGE_OFFSET;
+#ifdef CONFIG_KASAN
+	address_markers[KASAN_SHADOW_START_NR].start_address = KASAN_SHADOW_START;
+	address_markers[KASAN_SHADOW_END_NR].start_address = KASAN_SHADOW_END;
+#endif
 #ifdef CONFIG_64BIT
 	address_markers[MODULES_MAPPING_NR].start_address = MODULES_VADDR;
 	address_markers[KERNEL_MAPPING_NR].start_address = kernel_map.virt_addr;
-- 
2.37.2


^ permalink raw reply related	[flat|nested] 10+ messages in thread

* [PATCH v2 6/6] riscv: Unconditionnally select KASAN_VMALLOC if KASAN
  2023-01-23 10:09 [PATCH v2 0/6] RISC-V kasan rework Alexandre Ghiti
                   ` (4 preceding siblings ...)
  2023-01-23 10:09 ` [PATCH v2 5/6] riscv: Fix ptdump when KASAN is enabled Alexandre Ghiti
@ 2023-01-23 10:09 ` Alexandre Ghiti
  5 siblings, 0 replies; 10+ messages in thread
From: Alexandre Ghiti @ 2023-01-23 10:09 UTC (permalink / raw)
  To: Paul Walmsley, Palmer Dabbelt, Albert Ou, Andrey Ryabinin,
	Alexander Potapenko, Andrey Konovalov, Dmitry Vyukov,
	Vincenzo Frascino, Ard Biesheuvel, linux-riscv, linux-kernel,
	kasan-dev, linux-efi
  Cc: Alexandre Ghiti

If KASAN is enabled, VMAP_STACK depends on KASAN_VMALLOC so enable
KASAN_VMALLOC with KASAN so that we can enable VMAP_STACK by default.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
---
 arch/riscv/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index e2b656043abf..0f226d3261ca 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -117,6 +117,7 @@ config RISCV
 	select HAVE_RSEQ
 	select IRQ_DOMAIN
 	select IRQ_FORCED_THREADING
+	select KASAN_VMALLOC if KASAN
 	select MODULES_USE_ELF_RELA if MODULES
 	select MODULE_SECTIONS if MODULES
 	select OF
-- 
2.37.2


^ permalink raw reply related	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2023-01-24  8:00 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2023-01-23 10:09 [PATCH v2 0/6] RISC-V kasan rework Alexandre Ghiti
2023-01-23 10:09 ` [PATCH v2 1/6] riscv: Split early and final KASAN population functions Alexandre Ghiti
2023-01-23 22:15   ` Conor Dooley
2023-01-24  8:00     ` Alexandre Ghiti
2023-01-23 10:09 ` [PATCH v2 2/6] riscv: Rework kasan " Alexandre Ghiti
2023-01-23 10:09 ` [PATCH v2 3/6] riscv: Move DTB_EARLY_BASE_VA to the kernel address space Alexandre Ghiti
2023-01-23 10:09 ` [PATCH v2 4/6] riscv: Fix EFI stub usage of KASAN instrumented strcmp function Alexandre Ghiti
2023-01-23 10:19   ` Ard Biesheuvel
2023-01-23 10:09 ` [PATCH v2 5/6] riscv: Fix ptdump when KASAN is enabled Alexandre Ghiti
2023-01-23 10:09 ` [PATCH v2 6/6] riscv: Unconditionnally select KASAN_VMALLOC if KASAN Alexandre Ghiti

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