Merge patch series "RISC-V kasan rework"

Alexandre Ghiti <alexghiti@rivosinc.com> says:

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 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.

* b4-shazam-merge:
  riscv: Unconditionnally select KASAN_VMALLOC if KASAN
  riscv: Fix ptdump when KASAN is enabled
  riscv: Fix EFI stub usage of KASAN instrumented strcmp function
  riscv: Move DTB_EARLY_BASE_VA to the kernel address space
  riscv: Rework kasan population functions
  riscv: Split early and final KASAN population functions

Link: https://lore.kernel.org/r/20230203075232.274282-1-alexghiti@rivosinc.comSigned-off-by: Palmer Dabbelt <palmer@rivosinc.com>

arch/riscv/Kconfig

@@ -120,6 +120,7 @@ config RISCV
 	select HAVE_SYSCALL_TRACEPOINTS
 	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

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;

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;
 

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;