Hi Shaoqin,
On 25/04/2023 08:04, Shaoqin Huang wrote:
Hi Nikos,
For that DABT_EL1 error, I have some clues about how it happens. It's
mainly because this patch includes a memory overflow. I will explain in
the code body.
Many thanks for this. This is the 2nd time I get caught by this :(
On 2/13/23 18:17, Nikos Nikoleris wrote:
This change implements an alternative setup sequence for the system
when we are booting through EFI. The memory map is discovered through
EFI boot services and devices through ACPI.
This change is based on a change initially proposed by
Andrew Jones <drjones@xxxxxxxxxx>
Signed-off-by: Nikos Nikoleris <nikos.nikoleris@xxxxxxx>
---
arm/cstart.S | 1 +
arm/cstart64.S | 1 +
lib/arm/asm/setup.h | 8 ++
lib/arm/setup.c | 181 +++++++++++++++++++++++++++++++++++++++++++-
lib/linux/efi.h | 1 +
5 files changed, 190 insertions(+), 2 deletions(-)
diff --git a/arm/cstart.S b/arm/cstart.S
index 7036e67f..3dd71ed9 100644
--- a/arm/cstart.S
+++ b/arm/cstart.S
@@ -242,6 +242,7 @@ asm_mmu_disable:
*
* Input r0 is the stack top, which is the exception stacks base
*/
+.globl exceptions_init
exceptions_init:
mrc p15, 0, r2, c1, c0, 0 @ read SCTLR
bic r2, #CR_V @ SCTLR.V := 0
diff --git a/arm/cstart64.S b/arm/cstart64.S
index e4ab7d06..223c1092 100644
--- a/arm/cstart64.S
+++ b/arm/cstart64.S
@@ -265,6 +265,7 @@ asm_mmu_disable:
* Vectors
*/
+.globl exceptions_init
exceptions_init:
adrp x4, vector_table
add x4, x4, :lo12:vector_table
diff --git a/lib/arm/asm/setup.h b/lib/arm/asm/setup.h
index 64cd379b..06069116 100644
--- a/lib/arm/asm/setup.h
+++ b/lib/arm/asm/setup.h
@@ -38,4 +38,12 @@ extern unsigned int mem_region_get_flags(phys_addr_t paddr);
void setup(const void *fdt, phys_addr_t freemem_start);
+#ifdef CONFIG_EFI
+
+#include <efi.h>
+
+efi_status_t setup_efi(efi_bootinfo_t *efi_bootinfo);
+
+#endif
+
#endif /* _ASMARM_SETUP_H_ */
diff --git a/lib/arm/setup.c b/lib/arm/setup.c
index 03a4098e..cab19b1e 100644
--- a/lib/arm/setup.c
+++ b/lib/arm/setup.c
@@ -33,7 +33,7 @@
#define NR_EXTRA_MEM_REGIONS 16
#define NR_INITIAL_MEM_REGIONS (MAX_DT_MEM_REGIONS + NR_EXTRA_MEM_REGIONS)
-extern unsigned long _etext;
+extern unsigned long _text, _etext, _data, _edata;
char *initrd;
u32 initrd_size;
@@ -43,7 +43,10 @@ int nr_cpus;
static struct mem_region __initial_mem_regions[NR_INITIAL_MEM_REGIONS + 1];
struct mem_region *mem_regions = __initial_mem_regions;
-phys_addr_t __phys_offset, __phys_end;
+phys_addr_t __phys_offset = (phys_addr_t)-1, __phys_end = 0;
+
+extern void exceptions_init(void);
+extern void asm_mmu_disable(void);
int mpidr_to_cpu(uint64_t mpidr)
{
@@ -289,3 +292,177 @@ void setup(const void *fdt, phys_addr_t freemem_start)
if (!(auxinfo.flags & AUXINFO_MMU_OFF))
setup_vm();
}
+
+#ifdef CONFIG_EFI
+
+#include <efi.h>
+
+static efi_status_t setup_rsdp(efi_bootinfo_t *efi_bootinfo)
+{
+ efi_status_t status;
+ struct acpi_table_rsdp *rsdp;
+
+ /*
+ * RSDP resides in an EFI_ACPI_RECLAIM_MEMORY region, which is not used
+ * by kvm-unit-tests arm64 memory allocator. So it is not necessary to
+ * copy the data structure to another memory region to prevent
+ * unintentional overwrite.
+ */
+ status = efi_get_system_config_table(ACPI_20_TABLE_GUID, (void **)&rsdp);
+ if (status != EFI_SUCCESS)
+ return status;
+
+ set_efi_rsdp(rsdp);
+
+ return EFI_SUCCESS;
+}
+
+static efi_status_t efi_mem_init(efi_bootinfo_t *efi_bootinfo)
+{
+ int i;
+ unsigned long free_mem_pages = 0;
+ unsigned long free_mem_start = 0;
+ struct efi_boot_memmap *map = &(efi_bootinfo->mem_map);
+ efi_memory_desc_t *buffer = *map->map;
+ efi_memory_desc_t *d = NULL;
+ phys_addr_t base, top;
+ struct mem_region *r;
+ uintptr_t text = (uintptr_t)&_text, etext = __ALIGN((uintptr_t)&_etext, 4096);
+ uintptr_t data = (uintptr_t)&_data, edata = __ALIGN((uintptr_t)&_edata, 4096);
+
+ /*
+ * Record the largest free EFI_CONVENTIONAL_MEMORY region
+ * which will be used to set up the memory allocator, so that
+ * the memory allocator can work in the largest free
+ * continuous memory region.
+ */
+ for (i = 0, r = &mem_regions[0]; i < *(map->map_size); i += *(map->desc_size), ++r) {
At here, we can see here use the mem_regions to record the
efi_boot_memmap information, so we will iterate the efi_boot_memmap
which has (*map->map_size)/(*map->desc_size) number of the structure.
Obviously, here didn't check if the mem_regions is fulled, so when the
efi_boot_memmap is bigger than the mem_regions, the memory overflow happens.
And when memory overflow happens, Coincidentally, the mmu_idmap is just
follow the memory of the mem_regions, so this iteration will write to
mmu_idmap memory, which cause the mmu_idmap not NULL, so when the first
time the __ioremap being called, which the call trace is:
efi_main->
setup_efi->
io_init->
uart0_init_acpi->
ioremap->
__ioremap
if (mmu_enabled()) {
pgtable = current_thread_info()->pgtable;
} else {
if (!mmu_idmap)
mmu_idmap = alloc_page();
pgtable = mmu_idmap;
}
When it first arrive at here, the mmu_idmap should be NULL, and a new
mmu_idmap will be allocated, but unfortunately, the mmu_idmap has been
write to a value, so it is not NULL, so the dirty mmu_idmap will be used
as a pgtable. Which cause the DABT_EL1 error when continue build the
page table.
And the solution is very easy, just make the mem_regions bigger, for
example:
static struct mem_region __initial_mem_regions[NR_INITIAL_MEM_REGIONS + 20];
struct mem_region *mem_regions = __initial_mem_regions;
After make it bigger, the DABT_EL1 error will not happen on my machine.
Hope it works for you.
Indeed, I can confirm that this is the issue I run into. It would be
nice if Drew can confirm as well. Just to be on the safe side in the v5
I will apply these changes.
Thanks,
Nikos
From a836dc91706cc9e9aee5ce6b8b659d74d98c7bd7 Mon Sep 17 00:00:00 2001
From: Nikos Nikoleris <nikos.nikoleris@xxxxxxx>
Date: Wed, 3 Aug 2022 13:47:56 +0100
Subject: [kvm-unit-tests PATCH] fixup! arm/arm64: Add a setup sequence
for systems that boot through EFI
X-ARM-No-Footer: FoSSMail
---
lib/arm/setup.c | 45 ++++++++++++++++++++++++---------------------
1 file changed, 24 insertions(+), 21 deletions(-)
diff --git a/lib/arm/setup.c b/lib/arm/setup.c
index cab19b1e..c4f495a9 100644
--- a/lib/arm/setup.c
+++ b/lib/arm/setup.c
@@ -30,7 +30,7 @@
#include "io.h"
#define MAX_DT_MEM_REGIONS 16
-#define NR_EXTRA_MEM_REGIONS 16
+#define NR_EXTRA_MEM_REGIONS 64
#define NR_INITIAL_MEM_REGIONS (MAX_DT_MEM_REGIONS + NR_EXTRA_MEM_REGIONS)
extern unsigned long _text, _etext, _data, _edata;
@@ -326,7 +326,7 @@ static efi_status_t efi_mem_init(efi_bootinfo_t
*efi_bootinfo)
efi_memory_desc_t *buffer = *map->map;
efi_memory_desc_t *d = NULL;
phys_addr_t base, top;
- struct mem_region *r;
+ struct mem_region r;
uintptr_t text = (uintptr_t)&_text, etext =
__ALIGN((uintptr_t)&_etext, 4096);
uintptr_t data = (uintptr_t)&_data, edata =
__ALIGN((uintptr_t)&_edata, 4096);
@@ -336,11 +336,12 @@ static efi_status_t efi_mem_init(efi_bootinfo_t
*efi_bootinfo)
* the memory allocator can work in the largest free
* continuous memory region.
*/
- for (i = 0, r = &mem_regions[0]; i < *(map->map_size); i +=
*(map->desc_size), ++r) {
+ for (i = 0; i < *(map->map_size); i += *(map->desc_size)) {
d = (efi_memory_desc_t *)(&((u8 *)buffer)[i]);
- r->start = d->phys_addr;
- r->end = d->phys_addr + d->num_pages * EFI_PAGE_SIZE;
+ r.start = d->phys_addr;
+ r.end = d->phys_addr + d->num_pages * EFI_PAGE_SIZE;
+ r.flags = 0;
switch (d->type) {
case EFI_RESERVED_TYPE:
@@ -353,26 +354,27 @@ static efi_status_t efi_mem_init(efi_bootinfo_t
*efi_bootinfo)
case EFI_ACPI_RECLAIM_MEMORY:
case EFI_ACPI_MEMORY_NVS:
case EFI_PAL_CODE:
- r->flags = MR_F_RESERVED;
+ r.flags = MR_F_RESERVED;
break;
case EFI_MEMORY_MAPPED_IO:
case EFI_MEMORY_MAPPED_IO_PORT_SPACE:
- r->flags = MR_F_IO;
+ r.flags = MR_F_IO;
break;
case EFI_LOADER_CODE:
- if (r->start <= text && r->end > text) {
+ if (r.start <= text && r.end > text) {
/* This is the unit test region. Flag the code separately. */
- phys_addr_t tmp = r->end;
+ phys_addr_t tmp = r.end;
assert(etext <= data);
- assert(edata <= r->end);
- r->flags = MR_F_CODE;
- r->end = data;
- ++r;
- r->start = data;
- r->end = tmp;
+ assert(edata <= r.end);
+ r.flags = MR_F_CODE;
+ r.end = data;
+ mem_region_add(&r);
+ r.start = data;
+ r.end = tmp;
+ r.flags = 0;
} else {
- r->flags = MR_F_RESERVED;
+ r.flags = MR_F_RESERVED;
}
break;
case EFI_CONVENTIONAL_MEMORY:
@@ -383,12 +385,13 @@ static efi_status_t efi_mem_init(efi_bootinfo_t
*efi_bootinfo)
break;
}
- if (!(r->flags & MR_F_IO)) {
- if (r->start < __phys_offset)
- __phys_offset = r->start;
- if (r->end > __phys_end)
- __phys_end = r->end;
+ if (!(r.flags & MR_F_IO)) {
+ if (r.start < __phys_offset)
+ __phys_offset = r.start;
+ if (r.end > __phys_end)
+ __phys_end = r.end;
}
+ mem_region_add(&r);
}
__phys_end &= PHYS_MASK;
asm_mmu_disable();
--
2.25.1
