* [PATCH V2 0/2] kexec-tools: arm64: Enable D-cache in purgatory
@ 2016-12-19 7:13 ` Pratyush Anand
0 siblings, 0 replies; 22+ messages in thread
From: Pratyush Anand @ 2016-12-19 7:13 UTC (permalink / raw)
To: linux-arm-kernel
It takes more that 2 minutes to verify SHA in purgatory when vmlinuz image
is around 13MB and initramfs is around 30MB. It takes more than 20 second
even when we have -O2 optimization enabled. However, if dcache is enabled
during purgatory execution then, it takes just a second in SHA
verification.
Therefore, these patches adds support for dcache enabling facility during
purgatory execution.
Although I have simplified the logic a bit now, however I understand that
there are reservations for introducing this complexity for gaining few
seconding of execution time during kexec or crash reboot. But, I believe
if d-cache enabling code is stable enough then there should not be any
hindrances to accept it. So, please give it a try with your platform and
let me know if you see any issue or it does not work. I am still open to
improve it further if needed.
Changes since V1:
- Moved page table creation logic from purgatory to kexec code.
- Only 4K page table is supported, with 48 bit VA and 2M block size
- if platform supports a 4K page size, then D-cache is always
enabled now.
Pratyush Anand (2):
kexec: arm64: create identity page table to be used in purgatory
arm64: enable d-cache support during purgatory sha verification
kexec/arch/arm64/kexec-arm64.c | 152 ++++++++++++++++++
purgatory/arch/arm64/Makefile | 1 +
purgatory/arch/arm64/cache.S | 281 +++++++++++++++++++++++++++++++++
purgatory/arch/arm64/purgatory-arm64.c | 5 +
4 files changed, 439 insertions(+)
create mode 100644 purgatory/arch/arm64/cache.S
--
2.7.4
^ permalink raw reply [flat|nested] 22+ messages in thread
* [PATCH V2 0/2] kexec-tools: arm64: Enable D-cache in purgatory
@ 2016-12-19 7:13 ` Pratyush Anand
0 siblings, 0 replies; 22+ messages in thread
From: Pratyush Anand @ 2016-12-19 7:13 UTC (permalink / raw)
To: kexec, geoff, james.morse
Cc: mark.rutland, Pratyush Anand, dyoung, linux-arm-kernel
It takes more that 2 minutes to verify SHA in purgatory when vmlinuz image
is around 13MB and initramfs is around 30MB. It takes more than 20 second
even when we have -O2 optimization enabled. However, if dcache is enabled
during purgatory execution then, it takes just a second in SHA
verification.
Therefore, these patches adds support for dcache enabling facility during
purgatory execution.
Although I have simplified the logic a bit now, however I understand that
there are reservations for introducing this complexity for gaining few
seconding of execution time during kexec or crash reboot. But, I believe
if d-cache enabling code is stable enough then there should not be any
hindrances to accept it. So, please give it a try with your platform and
let me know if you see any issue or it does not work. I am still open to
improve it further if needed.
Changes since V1:
- Moved page table creation logic from purgatory to kexec code.
- Only 4K page table is supported, with 48 bit VA and 2M block size
- if platform supports a 4K page size, then D-cache is always
enabled now.
Pratyush Anand (2):
kexec: arm64: create identity page table to be used in purgatory
arm64: enable d-cache support during purgatory sha verification
kexec/arch/arm64/kexec-arm64.c | 152 ++++++++++++++++++
purgatory/arch/arm64/Makefile | 1 +
purgatory/arch/arm64/cache.S | 281 +++++++++++++++++++++++++++++++++
purgatory/arch/arm64/purgatory-arm64.c | 5 +
4 files changed, 439 insertions(+)
create mode 100644 purgatory/arch/arm64/cache.S
--
2.7.4
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 22+ messages in thread
* [PATCH V2 1/2] kexec: arm64: create identity page table to be used in purgatory
2016-12-19 7:13 ` Pratyush Anand
@ 2016-12-19 7:13 ` Pratyush Anand
-1 siblings, 0 replies; 22+ messages in thread
From: Pratyush Anand @ 2016-12-19 7:13 UTC (permalink / raw)
To: linux-arm-kernel
Purgatory sha verification is very slow when D-cache is not enabled there.
We need to enable MMU as well to enable D-Cache.Therefore,we need to an
identity mapped page table in purgatory.
Since debugging is very difficult in purgatory therefore we prefer to do as
much work as possible in kexec.
This patch prepares page table for purgatory in advance. We support only 4K
page table,because it will be available on most of the platform. This page
table is passed to the purgatory as a new segment.
VA bit is fixed as 48, page table level is 3 where 3rd level page table
contains 2M block entries.
Signed-off-by: Pratyush Anand <panand@redhat.com>
---
kexec/arch/arm64/kexec-arm64.c | 152 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 152 insertions(+)
diff --git a/kexec/arch/arm64/kexec-arm64.c b/kexec/arch/arm64/kexec-arm64.c
index 04fd3968bb52..c2c8ff1b6940 100644
--- a/kexec/arch/arm64/kexec-arm64.c
+++ b/kexec/arch/arm64/kexec-arm64.c
@@ -24,6 +24,45 @@
#include "kexec-syscall.h"
#include "arch/options.h"
+/*
+ * kexec creates identity page table to be used in purgatory so that
+ * dcache verification becomes faster.
+ *
+ * These are the definitions to be used by page table creation routine.
+ *
+ * Only 4K page table, 3 level, 2M block mapping, 48bit VA is supported
+ */
+#define PGDIR_SHIFT 39
+#define PUD_SHIFT 30
+#define PMD_SHIFT 21
+#define PTRS_PER_PGD 0x1FF
+#define PTRS_PER_PUD 0x1FF
+#define PTRS_PER_PMD 0x1FF
+#define PMD_TYPE_TABLE (3UL << 0)
+#define PMD_TYPE_SECT (1UL << 0)
+#define PMD_SECT_AF (1UL << 10)
+#define PMD_ATTRINDX(t) ((unsigned long)(t) << 2)
+#define MT_NORMAL 4
+#define PMD_FLAGS_NORMAL (PMD_TYPE_SECT | PMD_SECT_AF)
+#define MMU_FLAGS_NORMAL (PMD_ATTRINDX(MT_NORMAL) | PMD_FLAGS_NORMAL)
+#define SECTION_SIZE (2 * 1024 * 1024)
+#define PAGE_SIZE (4 * 1024)
+/* Since we are using 3 level of page tables, therefore minimum number of
+ * table will be 3. Most likely we will never need more than 3. Each entry
+ * in level 3 page table can map 2MB memory area. Thus a level 3 page table
+ * indexed by bit 29:21 can map a total of 1G memory area. Therefore, if
+ * any segment crosses 1G boundary, then we will need one more level 3
+ * table. Similarly, level 2 page table indexed by bit 38:30 can map a
+ * total of 512G memory area. If segment addresses are more than 512G apart
+ * then we will need two more table for each such block. We do not expect
+ * any memory segment to cross 512G boundary, however if we will ever wish
+ * to support uart debugging in purgatory then that might cross the
+ * boundary and therefore additional 2 more table space. Thus we will need
+ * maximum of 6 table space.
+ */
+#define MAX_PGTBLE_SZ (6 * 4096)
+static int next_tbl_cnt = 1;
+
/* Global varables the core kexec routines expect. */
unsigned char reuse_initrd;
@@ -316,6 +355,117 @@ unsigned long arm64_locate_kernel_segment(struct kexec_info *info)
return hole;
}
+static unsigned long *create_table_entry(unsigned long *pgtbl_buf,
+ unsigned long pgtbl_mem, unsigned long *tbl,
+ unsigned long virt, int shift,
+ unsigned long ptrs)
+{
+ unsigned long index, desc, offset;
+
+ index = (virt >> shift) & ptrs;
+ /* check if we have allocated a table already for this index */
+ if (tbl[index]) {
+ /*
+ * table index will have entry as per purgatory page table
+ * memory. Find out corresponding buffer address of table.
+ */
+ desc = tbl[index] & ~3UL;
+ offset = desc - pgtbl_mem;
+ return &pgtbl_buf[offset >> 3];
+ }
+
+ /*
+ * Always write page table content as per page table memory allocated
+ * for purgaory area, but return corresponding buffer area alloced
+ * in kexec
+ */
+ if (next_tbl_cnt > 5)
+ die("%s: No more memory for page table\n", __func__);
+
+ tbl[index] = (pgtbl_mem + PAGE_SIZE * next_tbl_cnt) | PMD_TYPE_TABLE;
+
+ return &pgtbl_buf[(next_tbl_cnt++ * PAGE_SIZE) >> 3];
+}
+
+static void craete_block_entry(unsigned long *tbl, unsigned long flags,
+ unsigned long phys, unsigned long virt)
+{
+ unsigned long index;
+ unsigned long desc;
+
+ index = (virt >> PMD_SHIFT) & PTRS_PER_PMD;
+ desc = (phys >> PMD_SHIFT) << PMD_SHIFT;
+ desc |= flags;
+ tbl[index] = desc;
+}
+
+static void create_identity_entry(unsigned long *pgtbl_buf,
+ unsigned long pgtbl_mem, unsigned long virt,
+ unsigned long flags)
+{
+ unsigned long *tbl = pgtbl_buf;
+
+ tbl = create_table_entry(pgtbl_buf, pgtbl_mem, tbl, virt,
+ PGDIR_SHIFT, PTRS_PER_PGD);
+ tbl = create_table_entry(pgtbl_buf, pgtbl_mem, tbl, virt,
+ PUD_SHIFT, PTRS_PER_PUD);
+ craete_block_entry(tbl, flags, virt, virt);
+}
+
+/**
+ * arm64_create_pgtbl_segment - Create page table segments to be used by
+ * purgatory. Page table will have entries to access memory area of all
+ * those segments which becomes part of sha verification in purgatory.
+ * Additionaly, we also create page table for purgatory segment as well.
+ */
+
+static int arm64_create_pgtbl_segment(struct kexec_info *info,
+ unsigned long hole_min, unsigned long hole_max)
+{
+ unsigned long *pgtbl_buf;
+ int i;
+ unsigned long mstart, mend, pgtbl_mem;
+ unsigned long purgatory_base, purgatory_len;
+
+ pgtbl_buf = xmalloc(MAX_PGTBLE_SZ);
+ memset(pgtbl_buf, 0, MAX_PGTBLE_SZ);
+ pgtbl_mem = add_buffer_phys_virt(info, pgtbl_buf, MAX_PGTBLE_SZ,
+ MAX_PGTBLE_SZ, PAGE_SIZE, hole_min, hole_max, 1, 0);
+ for (i = 0; i < info->nr_segments; i++) {
+ if (info->segment[i].mem == (void *)info->rhdr.rel_addr) {
+ purgatory_base = (unsigned long)info->segment[i].mem;
+ purgatory_len = info->segment[i].memsz;
+ }
+ mstart = (unsigned long)info->segment[i].mem;
+ mend = mstart + info->segment[i].memsz;
+ mstart &= ~(SECTION_SIZE - 1);
+ while (mstart < mend) {
+ create_identity_entry(pgtbl_buf, pgtbl_mem,
+ mstart, MMU_FLAGS_NORMAL);
+ mstart += SECTION_SIZE;
+ }
+ }
+
+ /* we will need pgtble_base in purgatory for enabling d-cache */
+ elf_rel_set_symbol(&info->rhdr, "pgtble_base", &pgtbl_mem,
+ sizeof(pgtbl_mem));
+ /*
+ * We need to disable d-cache before we exit from purgatory.
+ * Since, only dcache flush by VAs is recomeneded, therefore we
+ * will also need memory location of all those area which will be
+ * accessed in purgatory with enabled d-cache. sha256_regions
+ * already have start and length for all the segments except
+ * purgatory. Therefore, we will need to pass start and length of
+ * purgatory additionaly.
+ */
+ elf_rel_set_symbol(&info->rhdr, "purgatory_base", &purgatory_base,
+ sizeof(purgatory_base));
+ elf_rel_set_symbol(&info->rhdr, "purgatory_len", &purgatory_len,
+ sizeof(purgatory_len));
+
+ return 0;
+}
+
/**
* arm64_load_other_segments - Prepare the dtb, initrd and purgatory segments.
*/
@@ -423,6 +573,8 @@ int arm64_load_other_segments(struct kexec_info *info,
elf_rel_set_symbol(&info->rhdr, "arm64_dtb_addr", &dtb_base,
sizeof(dtb_base));
+ arm64_create_pgtbl_segment(info, hole_min, hole_max);
+
return 0;
}
--
2.7.4
^ permalink raw reply related [flat|nested] 22+ messages in thread
* [PATCH V2 1/2] kexec: arm64: create identity page table to be used in purgatory
@ 2016-12-19 7:13 ` Pratyush Anand
0 siblings, 0 replies; 22+ messages in thread
From: Pratyush Anand @ 2016-12-19 7:13 UTC (permalink / raw)
To: kexec, geoff, james.morse
Cc: mark.rutland, Pratyush Anand, dyoung, linux-arm-kernel
Purgatory sha verification is very slow when D-cache is not enabled there.
We need to enable MMU as well to enable D-Cache.Therefore,we need to an
identity mapped page table in purgatory.
Since debugging is very difficult in purgatory therefore we prefer to do as
much work as possible in kexec.
This patch prepares page table for purgatory in advance. We support only 4K
page table,because it will be available on most of the platform. This page
table is passed to the purgatory as a new segment.
VA bit is fixed as 48, page table level is 3 where 3rd level page table
contains 2M block entries.
Signed-off-by: Pratyush Anand <panand@redhat.com>
---
kexec/arch/arm64/kexec-arm64.c | 152 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 152 insertions(+)
diff --git a/kexec/arch/arm64/kexec-arm64.c b/kexec/arch/arm64/kexec-arm64.c
index 04fd3968bb52..c2c8ff1b6940 100644
--- a/kexec/arch/arm64/kexec-arm64.c
+++ b/kexec/arch/arm64/kexec-arm64.c
@@ -24,6 +24,45 @@
#include "kexec-syscall.h"
#include "arch/options.h"
+/*
+ * kexec creates identity page table to be used in purgatory so that
+ * dcache verification becomes faster.
+ *
+ * These are the definitions to be used by page table creation routine.
+ *
+ * Only 4K page table, 3 level, 2M block mapping, 48bit VA is supported
+ */
+#define PGDIR_SHIFT 39
+#define PUD_SHIFT 30
+#define PMD_SHIFT 21
+#define PTRS_PER_PGD 0x1FF
+#define PTRS_PER_PUD 0x1FF
+#define PTRS_PER_PMD 0x1FF
+#define PMD_TYPE_TABLE (3UL << 0)
+#define PMD_TYPE_SECT (1UL << 0)
+#define PMD_SECT_AF (1UL << 10)
+#define PMD_ATTRINDX(t) ((unsigned long)(t) << 2)
+#define MT_NORMAL 4
+#define PMD_FLAGS_NORMAL (PMD_TYPE_SECT | PMD_SECT_AF)
+#define MMU_FLAGS_NORMAL (PMD_ATTRINDX(MT_NORMAL) | PMD_FLAGS_NORMAL)
+#define SECTION_SIZE (2 * 1024 * 1024)
+#define PAGE_SIZE (4 * 1024)
+/* Since we are using 3 level of page tables, therefore minimum number of
+ * table will be 3. Most likely we will never need more than 3. Each entry
+ * in level 3 page table can map 2MB memory area. Thus a level 3 page table
+ * indexed by bit 29:21 can map a total of 1G memory area. Therefore, if
+ * any segment crosses 1G boundary, then we will need one more level 3
+ * table. Similarly, level 2 page table indexed by bit 38:30 can map a
+ * total of 512G memory area. If segment addresses are more than 512G apart
+ * then we will need two more table for each such block. We do not expect
+ * any memory segment to cross 512G boundary, however if we will ever wish
+ * to support uart debugging in purgatory then that might cross the
+ * boundary and therefore additional 2 more table space. Thus we will need
+ * maximum of 6 table space.
+ */
+#define MAX_PGTBLE_SZ (6 * 4096)
+static int next_tbl_cnt = 1;
+
/* Global varables the core kexec routines expect. */
unsigned char reuse_initrd;
@@ -316,6 +355,117 @@ unsigned long arm64_locate_kernel_segment(struct kexec_info *info)
return hole;
}
+static unsigned long *create_table_entry(unsigned long *pgtbl_buf,
+ unsigned long pgtbl_mem, unsigned long *tbl,
+ unsigned long virt, int shift,
+ unsigned long ptrs)
+{
+ unsigned long index, desc, offset;
+
+ index = (virt >> shift) & ptrs;
+ /* check if we have allocated a table already for this index */
+ if (tbl[index]) {
+ /*
+ * table index will have entry as per purgatory page table
+ * memory. Find out corresponding buffer address of table.
+ */
+ desc = tbl[index] & ~3UL;
+ offset = desc - pgtbl_mem;
+ return &pgtbl_buf[offset >> 3];
+ }
+
+ /*
+ * Always write page table content as per page table memory allocated
+ * for purgaory area, but return corresponding buffer area alloced
+ * in kexec
+ */
+ if (next_tbl_cnt > 5)
+ die("%s: No more memory for page table\n", __func__);
+
+ tbl[index] = (pgtbl_mem + PAGE_SIZE * next_tbl_cnt) | PMD_TYPE_TABLE;
+
+ return &pgtbl_buf[(next_tbl_cnt++ * PAGE_SIZE) >> 3];
+}
+
+static void craete_block_entry(unsigned long *tbl, unsigned long flags,
+ unsigned long phys, unsigned long virt)
+{
+ unsigned long index;
+ unsigned long desc;
+
+ index = (virt >> PMD_SHIFT) & PTRS_PER_PMD;
+ desc = (phys >> PMD_SHIFT) << PMD_SHIFT;
+ desc |= flags;
+ tbl[index] = desc;
+}
+
+static void create_identity_entry(unsigned long *pgtbl_buf,
+ unsigned long pgtbl_mem, unsigned long virt,
+ unsigned long flags)
+{
+ unsigned long *tbl = pgtbl_buf;
+
+ tbl = create_table_entry(pgtbl_buf, pgtbl_mem, tbl, virt,
+ PGDIR_SHIFT, PTRS_PER_PGD);
+ tbl = create_table_entry(pgtbl_buf, pgtbl_mem, tbl, virt,
+ PUD_SHIFT, PTRS_PER_PUD);
+ craete_block_entry(tbl, flags, virt, virt);
+}
+
+/**
+ * arm64_create_pgtbl_segment - Create page table segments to be used by
+ * purgatory. Page table will have entries to access memory area of all
+ * those segments which becomes part of sha verification in purgatory.
+ * Additionaly, we also create page table for purgatory segment as well.
+ */
+
+static int arm64_create_pgtbl_segment(struct kexec_info *info,
+ unsigned long hole_min, unsigned long hole_max)
+{
+ unsigned long *pgtbl_buf;
+ int i;
+ unsigned long mstart, mend, pgtbl_mem;
+ unsigned long purgatory_base, purgatory_len;
+
+ pgtbl_buf = xmalloc(MAX_PGTBLE_SZ);
+ memset(pgtbl_buf, 0, MAX_PGTBLE_SZ);
+ pgtbl_mem = add_buffer_phys_virt(info, pgtbl_buf, MAX_PGTBLE_SZ,
+ MAX_PGTBLE_SZ, PAGE_SIZE, hole_min, hole_max, 1, 0);
+ for (i = 0; i < info->nr_segments; i++) {
+ if (info->segment[i].mem == (void *)info->rhdr.rel_addr) {
+ purgatory_base = (unsigned long)info->segment[i].mem;
+ purgatory_len = info->segment[i].memsz;
+ }
+ mstart = (unsigned long)info->segment[i].mem;
+ mend = mstart + info->segment[i].memsz;
+ mstart &= ~(SECTION_SIZE - 1);
+ while (mstart < mend) {
+ create_identity_entry(pgtbl_buf, pgtbl_mem,
+ mstart, MMU_FLAGS_NORMAL);
+ mstart += SECTION_SIZE;
+ }
+ }
+
+ /* we will need pgtble_base in purgatory for enabling d-cache */
+ elf_rel_set_symbol(&info->rhdr, "pgtble_base", &pgtbl_mem,
+ sizeof(pgtbl_mem));
+ /*
+ * We need to disable d-cache before we exit from purgatory.
+ * Since, only dcache flush by VAs is recomeneded, therefore we
+ * will also need memory location of all those area which will be
+ * accessed in purgatory with enabled d-cache. sha256_regions
+ * already have start and length for all the segments except
+ * purgatory. Therefore, we will need to pass start and length of
+ * purgatory additionaly.
+ */
+ elf_rel_set_symbol(&info->rhdr, "purgatory_base", &purgatory_base,
+ sizeof(purgatory_base));
+ elf_rel_set_symbol(&info->rhdr, "purgatory_len", &purgatory_len,
+ sizeof(purgatory_len));
+
+ return 0;
+}
+
/**
* arm64_load_other_segments - Prepare the dtb, initrd and purgatory segments.
*/
@@ -423,6 +573,8 @@ int arm64_load_other_segments(struct kexec_info *info,
elf_rel_set_symbol(&info->rhdr, "arm64_dtb_addr", &dtb_base,
sizeof(dtb_base));
+ arm64_create_pgtbl_segment(info, hole_min, hole_max);
+
return 0;
}
--
2.7.4
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply related [flat|nested] 22+ messages in thread
* [PATCH V2 2/2] arm64: enable d-cache support during purgatory sha verification
2016-12-19 7:13 ` Pratyush Anand
@ 2016-12-19 7:13 ` Pratyush Anand
-1 siblings, 0 replies; 22+ messages in thread
From: Pratyush Anand @ 2016-12-19 7:13 UTC (permalink / raw)
To: linux-arm-kernel
If a platform supports 4K page table then enable D-cache in purgatory
before SHA verification. Disable it before switching to kernel.
Signed-off-by: Pratyush Anand <panand@redhat.com>
---
purgatory/arch/arm64/Makefile | 1 +
purgatory/arch/arm64/cache.S | 281 +++++++++++++++++++++++++++++++++
purgatory/arch/arm64/purgatory-arm64.c | 5 +
3 files changed, 287 insertions(+)
create mode 100644 purgatory/arch/arm64/cache.S
diff --git a/purgatory/arch/arm64/Makefile b/purgatory/arch/arm64/Makefile
index 636abeab17b2..db28a0de6891 100644
--- a/purgatory/arch/arm64/Makefile
+++ b/purgatory/arch/arm64/Makefile
@@ -11,6 +11,7 @@ arm64_PURGATORY_EXTRA_CFLAGS = \
arm64_PURGATORY_SRCS += \
purgatory/arch/arm64/entry.S \
+ purgatory/arch/arm64/cache.S \
purgatory/arch/arm64/purgatory-arm64.c
dist += \
diff --git a/purgatory/arch/arm64/cache.S b/purgatory/arch/arm64/cache.S
new file mode 100644
index 000000000000..48123866ad5f
--- /dev/null
+++ b/purgatory/arch/arm64/cache.S
@@ -0,0 +1,281 @@
+/*
+ * Some of the routines have been copied from Linux Kernel, therefore
+ * copying the license as well.
+ *
+ * Copyright (C) 2001 Deep Blue Solutions Ltd.
+ * Copyright (C) 2012 ARM Ltd.
+ * Copyright (C) 2016 Pratyush Anand <panand@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#define SCTLR_ELx_I (1 << 12)
+#define SCTLR_ELx_C (1 << 2)
+#define SCTLR_ELx_M (1 << 0)
+#define SCTLR_ELx_FLAGS (SCTLR_ELx_M | SCTLR_ELx_C | SCTLR_ELx_I)
+#define TCR_SHARED_NONE (0 << 12)
+#define TCR_ORGN_WBWA (1 << 10)
+#define TCR_IRGN_WBWA (1 << 8)
+#define TCR_T0SZ_48 16
+#define TCR_TG0_4K (0 << 14)
+#define TCR_FLAGS (TCR_SHARED_NONE | TCR_ORGN_WBWA |\
+ TCR_IRGN_WBWA | TCR_T0SZ_48 | TCR_TG0_4K)
+#define TCR_IPS_EL1_SHIFT 32
+#define TCR_IPS_EL2_SHIFT 16
+#define ID_AA64MMFR0_TGRAN4_SHIFT 28
+#define ID_AA64MMFR0_PARANGE_MASK 0xF
+#define MT_NORMAL 4
+#define MEMORY_ATTRIBUTES (0xFF << (MT_NORMAL*8))
+
+/*
+ * dcache_line_size - get the minimum D-cache line size from the CTR register.
+ */
+ .macro dcache_line_size, reg, tmp
+ mrs \tmp, ctr_el0 // read CTR
+ ubfm \tmp, \tmp, #16, #19 // cache line size encoding
+ mov \reg, #4 // bytes per word
+ lsl \reg, \reg, \tmp // actual cache line size
+ .endm
+
+/*
+ * flush_dcache_range(start, end)
+ * - x0 - start - start address of region
+ * - x1 - end - end address of region
+ *
+ */
+flush_dcache_range:
+ dcache_line_size x2, x3
+ sub x3, x2, #1
+ bic x0, x0, x3
+1: dc civac, x0 // clean & invalidate D line / unified line
+ add x0, x0, x2
+ cmp x0, x1
+ b.lo 1b
+ dsb sy
+ ret
+
+/*
+ * invalidate_tlbs_el1()
+ */
+invalidate_tlbs_el1:
+ dsb nshst
+ tlbi vmalle1
+ dsb nsh
+ isb
+ ret
+
+/*
+ * invalidate_tlbs_el2()
+ */
+invalidate_tlbs_el2:
+ dsb nshst
+ tlbi alle2
+ dsb nsh
+ isb
+ ret
+/*
+ * is_4k_page_not_supported - return nonzero if 4k page is not supported
+ */
+is_4k_page_not_supported:
+ mrs x0, ID_AA64MMFR0_EL1
+ and x0, x0, #(0xF << ID_AA64MMFR0_TGRAN4_SHIFT)
+ ret
+
+/*
+ * get_ips_bits - return supported IPS bits
+ */
+get_ips_bits:
+ mrs x0, ID_AA64MMFR0_EL1
+ and x0, x0, #ID_AA64MMFR0_PARANGE_MASK
+ ret
+
+/*
+ * get_current_el - Get information about current exception level
+ */
+get_current_el:
+ mrs x0, CurrentEL
+ lsr x0, x0, #2
+ ret
+
+/*
+ * invalidate_icache - Invalidate I-cache
+ */
+invalidate_icache:
+ ic iallu
+ dsb nsh
+ isb
+ ret
+
+/*
+ * set_mair_tcr_ttbr_sctlr_el1(page_table, tcr_flags) - sets MAIR, TCR , TTBR and SCTLR registers
+ * x0 - page_table - Page Table Base
+ * x1 - tcr_flags - TCR Flags to be set
+ */
+set_mair_tcr_ttbr_sctlr_el1:
+ ldr x2, =MEMORY_ATTRIBUTES
+ msr mair_el1, x2
+ msr tcr_el1, x1
+ msr ttbr0_el1, x0
+ isb
+ mrs x0, sctlr_el1
+ ldr x3, =SCTLR_ELx_FLAGS
+ orr x0, x0, x3
+ msr sctlr_el1, x0
+ isb
+ ret
+
+/*
+ * set_mair_tcr_ttbr_sctlr_el2(page_table, tcr_flags) - sets MAIR, TCR , TTBR and SCTLR registers
+ * x0 - page_table - Page Table Base
+ * x1 - tcr_flags - TCR Flags to be set
+ */
+set_mair_tcr_ttbr_sctlr_el2:
+ ldr x2, =MEMORY_ATTRIBUTES
+ msr mair_el2, x2
+ msr tcr_el2, x1
+ msr ttbr0_el2, x0
+ isb
+ mrs x0, sctlr_el2
+ ldr x3, =SCTLR_ELx_FLAGS
+ orr x0, x0, x3
+ msr sctlr_el2, x0
+ isb
+ ret
+
+/*
+ * reset_sctlr_el1 - disables cache and mmu
+ */
+reset_sctlr_el1:
+ mrs x0, sctlr_el1
+ bic x0, x0, #SCTLR_ELx_C
+ bic x0, x0, #SCTLR_ELx_M
+ msr sctlr_el1, x0
+ isb
+ ret
+
+/*
+ * reset_sctlr_el2 - disables cache and mmu
+ */
+reset_sctlr_el2:
+ mrs x0, sctlr_el2
+ bic x0, x0, #SCTLR_ELx_C
+ bic x0, x0, #SCTLR_ELx_M
+ msr sctlr_el2, x0
+ isb
+ ret
+
+.globl enable_dcache
+/*
+ * x6 - pgtble_base
+ * x7 - tcr_flags
+ * x8 - current_el
+ */
+enable_dcache:
+ stp x29, x30, [sp,#-16]!
+ stp x6, x7, [sp,#-16]!
+ stp x8, x9, [sp,#-16]!
+ bl is_4k_page_not_supported
+ cmp x0, #0
+ b.ne 1f
+ ldr x6, pgtble_base
+ ldr x7, =TCR_FLAGS
+ bl get_current_el
+ mov x8, x0
+ cmp x8, #2
+ b.ne 2f
+ bl invalidate_tlbs_el2
+ bl get_ips_bits
+ lsl x1, x0, #TCR_IPS_EL2_SHIFT
+ orr x1, x1, x7
+ mov x0, x6
+ bl set_mair_tcr_ttbr_sctlr_el2
+ b 1f
+2:
+ cmp x8, #1
+ b.ne 1f
+ bl invalidate_tlbs_el1
+ bl get_ips_bits
+ lsl x1, x0, #TCR_IPS_EL1_SHIFT
+ orr x1, x1, x7
+ mov x0, x6
+ bl set_mair_tcr_ttbr_sctlr_el1
+1:
+ ldp x8, x9, [sp],#16
+ ldp x6, x7, [sp],#16
+ ldp x29, x30, [sp],#16
+ ret
+
+.extern sha256_regions
+.globl disable_dcache
+/*
+ * x6 - pgtble_base
+ * x7 - current_el
+ */
+disable_dcache:
+ stp x29, x30, [sp,#-16]!
+ stp x6, x7, [sp,#-16]!
+ bl is_4k_page_not_supported
+ cmp x0, #0
+ b.ne 1f
+ ldr x6, pgtble_base
+ bl get_current_el
+ mov x7, x0
+ cmp x7, #2
+ b.ne 2f
+ bl reset_sctlr_el2
+ b 3f
+2:
+ cmp x7, #1
+ b.ne 1f
+ bl reset_sctlr_el1
+3:
+ /*
+ * we can only branch to function which does not use stack, until
+ * all memories are flushed.
+ */
+ bl invalidate_icache
+ /* flush d cache for purgatory region */
+ ldr x0, purgatory_base
+ ldr x1, purgatory_len
+ add x1, x1, x0
+ bl flush_dcache_range
+ /* flush d cache for rest of the regions */
+ ldr x6, =sha256_regions
+4:
+ ldp x0, x1, [x6],#16
+ cmp x1, #0
+ b.eq 1f
+ add x1, x1, x0
+ bl flush_dcache_range
+ b 4b
+1:
+ ldp x6, x7, [sp],#16
+ ldp x29, x30, [sp],#16
+ ret
+
+.align 3
+
+.globl pgtble_base
+pgtble_base:
+ .quad 0
+ .size pgtble_base, .-pgtble_base
+
+.globl purgatory_base
+purgatory_base:
+ .quad 0
+ .size purgatory_base, .-purgatory_base
+
+.globl purgatory_len
+purgatory_len:
+ .quad 0
+ .size purgatory_len, .-purgatory_len
diff --git a/purgatory/arch/arm64/purgatory-arm64.c b/purgatory/arch/arm64/purgatory-arm64.c
index fe50fcf8ebc3..638fb11d9843 100644
--- a/purgatory/arch/arm64/purgatory-arm64.c
+++ b/purgatory/arch/arm64/purgatory-arm64.c
@@ -5,6 +5,9 @@
#include <stdint.h>
#include <purgatory.h>
+void enable_dcache(void);
+void disable_dcache(void);
+
void putchar(int ch)
{
/* Nothing for now */
@@ -12,8 +15,10 @@ void putchar(int ch)
void post_verification_setup_arch(void)
{
+ disable_dcache();
}
void setup_arch(void)
{
+ enable_dcache();
}
--
2.7.4
^ permalink raw reply related [flat|nested] 22+ messages in thread
* [PATCH V2 2/2] arm64: enable d-cache support during purgatory sha verification
@ 2016-12-19 7:13 ` Pratyush Anand
0 siblings, 0 replies; 22+ messages in thread
From: Pratyush Anand @ 2016-12-19 7:13 UTC (permalink / raw)
To: kexec, geoff, james.morse
Cc: mark.rutland, Pratyush Anand, dyoung, linux-arm-kernel
If a platform supports 4K page table then enable D-cache in purgatory
before SHA verification. Disable it before switching to kernel.
Signed-off-by: Pratyush Anand <panand@redhat.com>
---
purgatory/arch/arm64/Makefile | 1 +
purgatory/arch/arm64/cache.S | 281 +++++++++++++++++++++++++++++++++
purgatory/arch/arm64/purgatory-arm64.c | 5 +
3 files changed, 287 insertions(+)
create mode 100644 purgatory/arch/arm64/cache.S
diff --git a/purgatory/arch/arm64/Makefile b/purgatory/arch/arm64/Makefile
index 636abeab17b2..db28a0de6891 100644
--- a/purgatory/arch/arm64/Makefile
+++ b/purgatory/arch/arm64/Makefile
@@ -11,6 +11,7 @@ arm64_PURGATORY_EXTRA_CFLAGS = \
arm64_PURGATORY_SRCS += \
purgatory/arch/arm64/entry.S \
+ purgatory/arch/arm64/cache.S \
purgatory/arch/arm64/purgatory-arm64.c
dist += \
diff --git a/purgatory/arch/arm64/cache.S b/purgatory/arch/arm64/cache.S
new file mode 100644
index 000000000000..48123866ad5f
--- /dev/null
+++ b/purgatory/arch/arm64/cache.S
@@ -0,0 +1,281 @@
+/*
+ * Some of the routines have been copied from Linux Kernel, therefore
+ * copying the license as well.
+ *
+ * Copyright (C) 2001 Deep Blue Solutions Ltd.
+ * Copyright (C) 2012 ARM Ltd.
+ * Copyright (C) 2016 Pratyush Anand <panand@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#define SCTLR_ELx_I (1 << 12)
+#define SCTLR_ELx_C (1 << 2)
+#define SCTLR_ELx_M (1 << 0)
+#define SCTLR_ELx_FLAGS (SCTLR_ELx_M | SCTLR_ELx_C | SCTLR_ELx_I)
+#define TCR_SHARED_NONE (0 << 12)
+#define TCR_ORGN_WBWA (1 << 10)
+#define TCR_IRGN_WBWA (1 << 8)
+#define TCR_T0SZ_48 16
+#define TCR_TG0_4K (0 << 14)
+#define TCR_FLAGS (TCR_SHARED_NONE | TCR_ORGN_WBWA |\
+ TCR_IRGN_WBWA | TCR_T0SZ_48 | TCR_TG0_4K)
+#define TCR_IPS_EL1_SHIFT 32
+#define TCR_IPS_EL2_SHIFT 16
+#define ID_AA64MMFR0_TGRAN4_SHIFT 28
+#define ID_AA64MMFR0_PARANGE_MASK 0xF
+#define MT_NORMAL 4
+#define MEMORY_ATTRIBUTES (0xFF << (MT_NORMAL*8))
+
+/*
+ * dcache_line_size - get the minimum D-cache line size from the CTR register.
+ */
+ .macro dcache_line_size, reg, tmp
+ mrs \tmp, ctr_el0 // read CTR
+ ubfm \tmp, \tmp, #16, #19 // cache line size encoding
+ mov \reg, #4 // bytes per word
+ lsl \reg, \reg, \tmp // actual cache line size
+ .endm
+
+/*
+ * flush_dcache_range(start, end)
+ * - x0 - start - start address of region
+ * - x1 - end - end address of region
+ *
+ */
+flush_dcache_range:
+ dcache_line_size x2, x3
+ sub x3, x2, #1
+ bic x0, x0, x3
+1: dc civac, x0 // clean & invalidate D line / unified line
+ add x0, x0, x2
+ cmp x0, x1
+ b.lo 1b
+ dsb sy
+ ret
+
+/*
+ * invalidate_tlbs_el1()
+ */
+invalidate_tlbs_el1:
+ dsb nshst
+ tlbi vmalle1
+ dsb nsh
+ isb
+ ret
+
+/*
+ * invalidate_tlbs_el2()
+ */
+invalidate_tlbs_el2:
+ dsb nshst
+ tlbi alle2
+ dsb nsh
+ isb
+ ret
+/*
+ * is_4k_page_not_supported - return nonzero if 4k page is not supported
+ */
+is_4k_page_not_supported:
+ mrs x0, ID_AA64MMFR0_EL1
+ and x0, x0, #(0xF << ID_AA64MMFR0_TGRAN4_SHIFT)
+ ret
+
+/*
+ * get_ips_bits - return supported IPS bits
+ */
+get_ips_bits:
+ mrs x0, ID_AA64MMFR0_EL1
+ and x0, x0, #ID_AA64MMFR0_PARANGE_MASK
+ ret
+
+/*
+ * get_current_el - Get information about current exception level
+ */
+get_current_el:
+ mrs x0, CurrentEL
+ lsr x0, x0, #2
+ ret
+
+/*
+ * invalidate_icache - Invalidate I-cache
+ */
+invalidate_icache:
+ ic iallu
+ dsb nsh
+ isb
+ ret
+
+/*
+ * set_mair_tcr_ttbr_sctlr_el1(page_table, tcr_flags) - sets MAIR, TCR , TTBR and SCTLR registers
+ * x0 - page_table - Page Table Base
+ * x1 - tcr_flags - TCR Flags to be set
+ */
+set_mair_tcr_ttbr_sctlr_el1:
+ ldr x2, =MEMORY_ATTRIBUTES
+ msr mair_el1, x2
+ msr tcr_el1, x1
+ msr ttbr0_el1, x0
+ isb
+ mrs x0, sctlr_el1
+ ldr x3, =SCTLR_ELx_FLAGS
+ orr x0, x0, x3
+ msr sctlr_el1, x0
+ isb
+ ret
+
+/*
+ * set_mair_tcr_ttbr_sctlr_el2(page_table, tcr_flags) - sets MAIR, TCR , TTBR and SCTLR registers
+ * x0 - page_table - Page Table Base
+ * x1 - tcr_flags - TCR Flags to be set
+ */
+set_mair_tcr_ttbr_sctlr_el2:
+ ldr x2, =MEMORY_ATTRIBUTES
+ msr mair_el2, x2
+ msr tcr_el2, x1
+ msr ttbr0_el2, x0
+ isb
+ mrs x0, sctlr_el2
+ ldr x3, =SCTLR_ELx_FLAGS
+ orr x0, x0, x3
+ msr sctlr_el2, x0
+ isb
+ ret
+
+/*
+ * reset_sctlr_el1 - disables cache and mmu
+ */
+reset_sctlr_el1:
+ mrs x0, sctlr_el1
+ bic x0, x0, #SCTLR_ELx_C
+ bic x0, x0, #SCTLR_ELx_M
+ msr sctlr_el1, x0
+ isb
+ ret
+
+/*
+ * reset_sctlr_el2 - disables cache and mmu
+ */
+reset_sctlr_el2:
+ mrs x0, sctlr_el2
+ bic x0, x0, #SCTLR_ELx_C
+ bic x0, x0, #SCTLR_ELx_M
+ msr sctlr_el2, x0
+ isb
+ ret
+
+.globl enable_dcache
+/*
+ * x6 - pgtble_base
+ * x7 - tcr_flags
+ * x8 - current_el
+ */
+enable_dcache:
+ stp x29, x30, [sp,#-16]!
+ stp x6, x7, [sp,#-16]!
+ stp x8, x9, [sp,#-16]!
+ bl is_4k_page_not_supported
+ cmp x0, #0
+ b.ne 1f
+ ldr x6, pgtble_base
+ ldr x7, =TCR_FLAGS
+ bl get_current_el
+ mov x8, x0
+ cmp x8, #2
+ b.ne 2f
+ bl invalidate_tlbs_el2
+ bl get_ips_bits
+ lsl x1, x0, #TCR_IPS_EL2_SHIFT
+ orr x1, x1, x7
+ mov x0, x6
+ bl set_mair_tcr_ttbr_sctlr_el2
+ b 1f
+2:
+ cmp x8, #1
+ b.ne 1f
+ bl invalidate_tlbs_el1
+ bl get_ips_bits
+ lsl x1, x0, #TCR_IPS_EL1_SHIFT
+ orr x1, x1, x7
+ mov x0, x6
+ bl set_mair_tcr_ttbr_sctlr_el1
+1:
+ ldp x8, x9, [sp],#16
+ ldp x6, x7, [sp],#16
+ ldp x29, x30, [sp],#16
+ ret
+
+.extern sha256_regions
+.globl disable_dcache
+/*
+ * x6 - pgtble_base
+ * x7 - current_el
+ */
+disable_dcache:
+ stp x29, x30, [sp,#-16]!
+ stp x6, x7, [sp,#-16]!
+ bl is_4k_page_not_supported
+ cmp x0, #0
+ b.ne 1f
+ ldr x6, pgtble_base
+ bl get_current_el
+ mov x7, x0
+ cmp x7, #2
+ b.ne 2f
+ bl reset_sctlr_el2
+ b 3f
+2:
+ cmp x7, #1
+ b.ne 1f
+ bl reset_sctlr_el1
+3:
+ /*
+ * we can only branch to function which does not use stack, until
+ * all memories are flushed.
+ */
+ bl invalidate_icache
+ /* flush d cache for purgatory region */
+ ldr x0, purgatory_base
+ ldr x1, purgatory_len
+ add x1, x1, x0
+ bl flush_dcache_range
+ /* flush d cache for rest of the regions */
+ ldr x6, =sha256_regions
+4:
+ ldp x0, x1, [x6],#16
+ cmp x1, #0
+ b.eq 1f
+ add x1, x1, x0
+ bl flush_dcache_range
+ b 4b
+1:
+ ldp x6, x7, [sp],#16
+ ldp x29, x30, [sp],#16
+ ret
+
+.align 3
+
+.globl pgtble_base
+pgtble_base:
+ .quad 0
+ .size pgtble_base, .-pgtble_base
+
+.globl purgatory_base
+purgatory_base:
+ .quad 0
+ .size purgatory_base, .-purgatory_base
+
+.globl purgatory_len
+purgatory_len:
+ .quad 0
+ .size purgatory_len, .-purgatory_len
diff --git a/purgatory/arch/arm64/purgatory-arm64.c b/purgatory/arch/arm64/purgatory-arm64.c
index fe50fcf8ebc3..638fb11d9843 100644
--- a/purgatory/arch/arm64/purgatory-arm64.c
+++ b/purgatory/arch/arm64/purgatory-arm64.c
@@ -5,6 +5,9 @@
#include <stdint.h>
#include <purgatory.h>
+void enable_dcache(void);
+void disable_dcache(void);
+
void putchar(int ch)
{
/* Nothing for now */
@@ -12,8 +15,10 @@ void putchar(int ch)
void post_verification_setup_arch(void)
{
+ disable_dcache();
}
void setup_arch(void)
{
+ enable_dcache();
}
--
2.7.4
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply related [flat|nested] 22+ messages in thread
* [PATCH V2 1/2] kexec: arm64: create identity page table to be used in purgatory
2016-12-19 7:13 ` Pratyush Anand
@ 2016-12-19 7:21 ` Maxim Uvarov
-1 siblings, 0 replies; 22+ messages in thread
From: Maxim Uvarov @ 2016-12-19 7:21 UTC (permalink / raw)
To: linux-arm-kernel
2016-12-19 10:13 GMT+03:00 Pratyush Anand <panand@redhat.com>:
> Purgatory sha verification is very slow when D-cache is not enabled there.
> We need to enable MMU as well to enable D-Cache.Therefore,we need to an
> identity mapped page table in purgatory.
>
> Since debugging is very difficult in purgatory therefore we prefer to do as
> much work as possible in kexec.
>
> This patch prepares page table for purgatory in advance. We support only 4K
> page table,because it will be available on most of the platform. This page
> table is passed to the purgatory as a new segment.
>
> VA bit is fixed as 48, page table level is 3 where 3rd level page table
> contains 2M block entries.
>
> Signed-off-by: Pratyush Anand <panand@redhat.com>
> ---
> kexec/arch/arm64/kexec-arm64.c | 152 +++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 152 insertions(+)
>
> diff --git a/kexec/arch/arm64/kexec-arm64.c b/kexec/arch/arm64/kexec-arm64.c
> index 04fd3968bb52..c2c8ff1b6940 100644
> --- a/kexec/arch/arm64/kexec-arm64.c
> +++ b/kexec/arch/arm64/kexec-arm64.c
> @@ -24,6 +24,45 @@
> #include "kexec-syscall.h"
> #include "arch/options.h"
>
> +/*
> + * kexec creates identity page table to be used in purgatory so that
> + * dcache verification becomes faster.
> + *
> + * These are the definitions to be used by page table creation routine.
> + *
> + * Only 4K page table, 3 level, 2M block mapping, 48bit VA is supported
> + */
> +#define PGDIR_SHIFT 39
> +#define PUD_SHIFT 30
> +#define PMD_SHIFT 21
> +#define PTRS_PER_PGD 0x1FF
> +#define PTRS_PER_PUD 0x1FF
> +#define PTRS_PER_PMD 0x1FF
> +#define PMD_TYPE_TABLE (3UL << 0)
> +#define PMD_TYPE_SECT (1UL << 0)
> +#define PMD_SECT_AF (1UL << 10)
> +#define PMD_ATTRINDX(t) ((unsigned long)(t) << 2)
> +#define MT_NORMAL 4
> +#define PMD_FLAGS_NORMAL (PMD_TYPE_SECT | PMD_SECT_AF)
> +#define MMU_FLAGS_NORMAL (PMD_ATTRINDX(MT_NORMAL) | PMD_FLAGS_NORMAL)
> +#define SECTION_SIZE (2 * 1024 * 1024)
> +#define PAGE_SIZE (4 * 1024)
> +/* Since we are using 3 level of page tables, therefore minimum number of
> + * table will be 3. Most likely we will never need more than 3. Each entry
> + * in level 3 page table can map 2MB memory area. Thus a level 3 page table
> + * indexed by bit 29:21 can map a total of 1G memory area. Therefore, if
> + * any segment crosses 1G boundary, then we will need one more level 3
> + * table. Similarly, level 2 page table indexed by bit 38:30 can map a
> + * total of 512G memory area. If segment addresses are more than 512G apart
> + * then we will need two more table for each such block. We do not expect
> + * any memory segment to cross 512G boundary, however if we will ever wish
> + * to support uart debugging in purgatory then that might cross the
> + * boundary and therefore additional 2 more table space. Thus we will need
> + * maximum of 6 table space.
> + */
> +#define MAX_PGTBLE_SZ (6 * 4096)
> +static int next_tbl_cnt = 1;
> +
> /* Global varables the core kexec routines expect. */
>
> unsigned char reuse_initrd;
> @@ -316,6 +355,117 @@ unsigned long arm64_locate_kernel_segment(struct kexec_info *info)
> return hole;
> }
>
> +static unsigned long *create_table_entry(unsigned long *pgtbl_buf,
> + unsigned long pgtbl_mem, unsigned long *tbl,
> + unsigned long virt, int shift,
> + unsigned long ptrs)
> +{
> + unsigned long index, desc, offset;
> +
> + index = (virt >> shift) & ptrs;
> + /* check if we have allocated a table already for this index */
> + if (tbl[index]) {
> + /*
> + * table index will have entry as per purgatory page table
> + * memory. Find out corresponding buffer address of table.
> + */
> + desc = tbl[index] & ~3UL;
> + offset = desc - pgtbl_mem;
> + return &pgtbl_buf[offset >> 3];
> + }
> +
> + /*
> + * Always write page table content as per page table memory allocated
> + * for purgaory area, but return corresponding buffer area alloced
> + * in kexec
> + */
> + if (next_tbl_cnt > 5)
> + die("%s: No more memory for page table\n", __func__);
> +
> + tbl[index] = (pgtbl_mem + PAGE_SIZE * next_tbl_cnt) | PMD_TYPE_TABLE;
> +
> + return &pgtbl_buf[(next_tbl_cnt++ * PAGE_SIZE) >> 3];
> +}
> +
> +static void craete_block_entry(unsigned long *tbl, unsigned long flags,
typo in name
> + unsigned long phys, unsigned long virt)
> +{
> + unsigned long index;
> + unsigned long desc;
> +
> + index = (virt >> PMD_SHIFT) & PTRS_PER_PMD;
> + desc = (phys >> PMD_SHIFT) << PMD_SHIFT;
> + desc |= flags;
> + tbl[index] = desc;
> +}
> +
> +static void create_identity_entry(unsigned long *pgtbl_buf,
> + unsigned long pgtbl_mem, unsigned long virt,
> + unsigned long flags)
> +{
> + unsigned long *tbl = pgtbl_buf;
> +
> + tbl = create_table_entry(pgtbl_buf, pgtbl_mem, tbl, virt,
> + PGDIR_SHIFT, PTRS_PER_PGD);
> + tbl = create_table_entry(pgtbl_buf, pgtbl_mem, tbl, virt,
> + PUD_SHIFT, PTRS_PER_PUD);
> + craete_block_entry(tbl, flags, virt, virt);
> +}
> +
> +/**
> + * arm64_create_pgtbl_segment - Create page table segments to be used by
> + * purgatory. Page table will have entries to access memory area of all
> + * those segments which becomes part of sha verification in purgatory.
> + * Additionaly, we also create page table for purgatory segment as well.
> + */
> +
> +static int arm64_create_pgtbl_segment(struct kexec_info *info,
> + unsigned long hole_min, unsigned long hole_max)
> +{
> + unsigned long *pgtbl_buf;
> + int i;
> + unsigned long mstart, mend, pgtbl_mem;
> + unsigned long purgatory_base, purgatory_len;
> +
> + pgtbl_buf = xmalloc(MAX_PGTBLE_SZ);
> + memset(pgtbl_buf, 0, MAX_PGTBLE_SZ);
> + pgtbl_mem = add_buffer_phys_virt(info, pgtbl_buf, MAX_PGTBLE_SZ,
> + MAX_PGTBLE_SZ, PAGE_SIZE, hole_min, hole_max, 1, 0);
> + for (i = 0; i < info->nr_segments; i++) {
> + if (info->segment[i].mem == (void *)info->rhdr.rel_addr) {
> + purgatory_base = (unsigned long)info->segment[i].mem;
> + purgatory_len = info->segment[i].memsz;
> + }
> + mstart = (unsigned long)info->segment[i].mem;
> + mend = mstart + info->segment[i].memsz;
> + mstart &= ~(SECTION_SIZE - 1);
> + while (mstart < mend) {
> + create_identity_entry(pgtbl_buf, pgtbl_mem,
> + mstart, MMU_FLAGS_NORMAL);
> + mstart += SECTION_SIZE;
> + }
> + }
> +
> + /* we will need pgtble_base in purgatory for enabling d-cache */
> + elf_rel_set_symbol(&info->rhdr, "pgtble_base", &pgtbl_mem,
> + sizeof(pgtbl_mem));
> + /*
> + * We need to disable d-cache before we exit from purgatory.
> + * Since, only dcache flush by VAs is recomeneded, therefore we
> + * will also need memory location of all those area which will be
> + * accessed in purgatory with enabled d-cache. sha256_regions
> + * already have start and length for all the segments except
> + * purgatory. Therefore, we will need to pass start and length of
> + * purgatory additionaly.
> + */
> + elf_rel_set_symbol(&info->rhdr, "purgatory_base", &purgatory_base,
> + sizeof(purgatory_base));
> + elf_rel_set_symbol(&info->rhdr, "purgatory_len", &purgatory_len,
> + sizeof(purgatory_len));
> +
> + return 0;
> +}
> +
> /**
> * arm64_load_other_segments - Prepare the dtb, initrd and purgatory segments.
> */
> @@ -423,6 +573,8 @@ int arm64_load_other_segments(struct kexec_info *info,
> elf_rel_set_symbol(&info->rhdr, "arm64_dtb_addr", &dtb_base,
> sizeof(dtb_base));
>
> + arm64_create_pgtbl_segment(info, hole_min, hole_max);
> +
> return 0;
> }
>
> --
> 2.7.4
>
>
> _______________________________________________
> kexec mailing list
> kexec at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec
--
Best regards,
Maxim Uvarov
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH V2 1/2] kexec: arm64: create identity page table to be used in purgatory
@ 2016-12-19 7:21 ` Maxim Uvarov
0 siblings, 0 replies; 22+ messages in thread
From: Maxim Uvarov @ 2016-12-19 7:21 UTC (permalink / raw)
To: Pratyush Anand
Cc: mark.rutland, geoff, kexec, james.morse, Dave Young, linux-arm-kernel
2016-12-19 10:13 GMT+03:00 Pratyush Anand <panand@redhat.com>:
> Purgatory sha verification is very slow when D-cache is not enabled there.
> We need to enable MMU as well to enable D-Cache.Therefore,we need to an
> identity mapped page table in purgatory.
>
> Since debugging is very difficult in purgatory therefore we prefer to do as
> much work as possible in kexec.
>
> This patch prepares page table for purgatory in advance. We support only 4K
> page table,because it will be available on most of the platform. This page
> table is passed to the purgatory as a new segment.
>
> VA bit is fixed as 48, page table level is 3 where 3rd level page table
> contains 2M block entries.
>
> Signed-off-by: Pratyush Anand <panand@redhat.com>
> ---
> kexec/arch/arm64/kexec-arm64.c | 152 +++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 152 insertions(+)
>
> diff --git a/kexec/arch/arm64/kexec-arm64.c b/kexec/arch/arm64/kexec-arm64.c
> index 04fd3968bb52..c2c8ff1b6940 100644
> --- a/kexec/arch/arm64/kexec-arm64.c
> +++ b/kexec/arch/arm64/kexec-arm64.c
> @@ -24,6 +24,45 @@
> #include "kexec-syscall.h"
> #include "arch/options.h"
>
> +/*
> + * kexec creates identity page table to be used in purgatory so that
> + * dcache verification becomes faster.
> + *
> + * These are the definitions to be used by page table creation routine.
> + *
> + * Only 4K page table, 3 level, 2M block mapping, 48bit VA is supported
> + */
> +#define PGDIR_SHIFT 39
> +#define PUD_SHIFT 30
> +#define PMD_SHIFT 21
> +#define PTRS_PER_PGD 0x1FF
> +#define PTRS_PER_PUD 0x1FF
> +#define PTRS_PER_PMD 0x1FF
> +#define PMD_TYPE_TABLE (3UL << 0)
> +#define PMD_TYPE_SECT (1UL << 0)
> +#define PMD_SECT_AF (1UL << 10)
> +#define PMD_ATTRINDX(t) ((unsigned long)(t) << 2)
> +#define MT_NORMAL 4
> +#define PMD_FLAGS_NORMAL (PMD_TYPE_SECT | PMD_SECT_AF)
> +#define MMU_FLAGS_NORMAL (PMD_ATTRINDX(MT_NORMAL) | PMD_FLAGS_NORMAL)
> +#define SECTION_SIZE (2 * 1024 * 1024)
> +#define PAGE_SIZE (4 * 1024)
> +/* Since we are using 3 level of page tables, therefore minimum number of
> + * table will be 3. Most likely we will never need more than 3. Each entry
> + * in level 3 page table can map 2MB memory area. Thus a level 3 page table
> + * indexed by bit 29:21 can map a total of 1G memory area. Therefore, if
> + * any segment crosses 1G boundary, then we will need one more level 3
> + * table. Similarly, level 2 page table indexed by bit 38:30 can map a
> + * total of 512G memory area. If segment addresses are more than 512G apart
> + * then we will need two more table for each such block. We do not expect
> + * any memory segment to cross 512G boundary, however if we will ever wish
> + * to support uart debugging in purgatory then that might cross the
> + * boundary and therefore additional 2 more table space. Thus we will need
> + * maximum of 6 table space.
> + */
> +#define MAX_PGTBLE_SZ (6 * 4096)
> +static int next_tbl_cnt = 1;
> +
> /* Global varables the core kexec routines expect. */
>
> unsigned char reuse_initrd;
> @@ -316,6 +355,117 @@ unsigned long arm64_locate_kernel_segment(struct kexec_info *info)
> return hole;
> }
>
> +static unsigned long *create_table_entry(unsigned long *pgtbl_buf,
> + unsigned long pgtbl_mem, unsigned long *tbl,
> + unsigned long virt, int shift,
> + unsigned long ptrs)
> +{
> + unsigned long index, desc, offset;
> +
> + index = (virt >> shift) & ptrs;
> + /* check if we have allocated a table already for this index */
> + if (tbl[index]) {
> + /*
> + * table index will have entry as per purgatory page table
> + * memory. Find out corresponding buffer address of table.
> + */
> + desc = tbl[index] & ~3UL;
> + offset = desc - pgtbl_mem;
> + return &pgtbl_buf[offset >> 3];
> + }
> +
> + /*
> + * Always write page table content as per page table memory allocated
> + * for purgaory area, but return corresponding buffer area alloced
> + * in kexec
> + */
> + if (next_tbl_cnt > 5)
> + die("%s: No more memory for page table\n", __func__);
> +
> + tbl[index] = (pgtbl_mem + PAGE_SIZE * next_tbl_cnt) | PMD_TYPE_TABLE;
> +
> + return &pgtbl_buf[(next_tbl_cnt++ * PAGE_SIZE) >> 3];
> +}
> +
> +static void craete_block_entry(unsigned long *tbl, unsigned long flags,
typo in name
> + unsigned long phys, unsigned long virt)
> +{
> + unsigned long index;
> + unsigned long desc;
> +
> + index = (virt >> PMD_SHIFT) & PTRS_PER_PMD;
> + desc = (phys >> PMD_SHIFT) << PMD_SHIFT;
> + desc |= flags;
> + tbl[index] = desc;
> +}
> +
> +static void create_identity_entry(unsigned long *pgtbl_buf,
> + unsigned long pgtbl_mem, unsigned long virt,
> + unsigned long flags)
> +{
> + unsigned long *tbl = pgtbl_buf;
> +
> + tbl = create_table_entry(pgtbl_buf, pgtbl_mem, tbl, virt,
> + PGDIR_SHIFT, PTRS_PER_PGD);
> + tbl = create_table_entry(pgtbl_buf, pgtbl_mem, tbl, virt,
> + PUD_SHIFT, PTRS_PER_PUD);
> + craete_block_entry(tbl, flags, virt, virt);
> +}
> +
> +/**
> + * arm64_create_pgtbl_segment - Create page table segments to be used by
> + * purgatory. Page table will have entries to access memory area of all
> + * those segments which becomes part of sha verification in purgatory.
> + * Additionaly, we also create page table for purgatory segment as well.
> + */
> +
> +static int arm64_create_pgtbl_segment(struct kexec_info *info,
> + unsigned long hole_min, unsigned long hole_max)
> +{
> + unsigned long *pgtbl_buf;
> + int i;
> + unsigned long mstart, mend, pgtbl_mem;
> + unsigned long purgatory_base, purgatory_len;
> +
> + pgtbl_buf = xmalloc(MAX_PGTBLE_SZ);
> + memset(pgtbl_buf, 0, MAX_PGTBLE_SZ);
> + pgtbl_mem = add_buffer_phys_virt(info, pgtbl_buf, MAX_PGTBLE_SZ,
> + MAX_PGTBLE_SZ, PAGE_SIZE, hole_min, hole_max, 1, 0);
> + for (i = 0; i < info->nr_segments; i++) {
> + if (info->segment[i].mem == (void *)info->rhdr.rel_addr) {
> + purgatory_base = (unsigned long)info->segment[i].mem;
> + purgatory_len = info->segment[i].memsz;
> + }
> + mstart = (unsigned long)info->segment[i].mem;
> + mend = mstart + info->segment[i].memsz;
> + mstart &= ~(SECTION_SIZE - 1);
> + while (mstart < mend) {
> + create_identity_entry(pgtbl_buf, pgtbl_mem,
> + mstart, MMU_FLAGS_NORMAL);
> + mstart += SECTION_SIZE;
> + }
> + }
> +
> + /* we will need pgtble_base in purgatory for enabling d-cache */
> + elf_rel_set_symbol(&info->rhdr, "pgtble_base", &pgtbl_mem,
> + sizeof(pgtbl_mem));
> + /*
> + * We need to disable d-cache before we exit from purgatory.
> + * Since, only dcache flush by VAs is recomeneded, therefore we
> + * will also need memory location of all those area which will be
> + * accessed in purgatory with enabled d-cache. sha256_regions
> + * already have start and length for all the segments except
> + * purgatory. Therefore, we will need to pass start and length of
> + * purgatory additionaly.
> + */
> + elf_rel_set_symbol(&info->rhdr, "purgatory_base", &purgatory_base,
> + sizeof(purgatory_base));
> + elf_rel_set_symbol(&info->rhdr, "purgatory_len", &purgatory_len,
> + sizeof(purgatory_len));
> +
> + return 0;
> +}
> +
> /**
> * arm64_load_other_segments - Prepare the dtb, initrd and purgatory segments.
> */
> @@ -423,6 +573,8 @@ int arm64_load_other_segments(struct kexec_info *info,
> elf_rel_set_symbol(&info->rhdr, "arm64_dtb_addr", &dtb_base,
> sizeof(dtb_base));
>
> + arm64_create_pgtbl_segment(info, hole_min, hole_max);
> +
> return 0;
> }
>
> --
> 2.7.4
>
>
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec
--
Best regards,
Maxim Uvarov
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 22+ messages in thread
* [PATCH V2 1/2] kexec: arm64: create identity page table to be used in purgatory
2016-12-19 7:21 ` Maxim Uvarov
@ 2016-12-19 7:23 ` Pratyush Anand
-1 siblings, 0 replies; 22+ messages in thread
From: Pratyush Anand @ 2016-12-19 7:23 UTC (permalink / raw)
To: linux-arm-kernel
On Monday 19 December 2016 12:51 PM, Maxim Uvarov wrote:
>> +
>> > +static void craete_block_entry(unsigned long *tbl, unsigned long flags,
> typo in name
>
Thanks.
Will fix.
~Pratyush
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH V2 1/2] kexec: arm64: create identity page table to be used in purgatory
@ 2016-12-19 7:23 ` Pratyush Anand
0 siblings, 0 replies; 22+ messages in thread
From: Pratyush Anand @ 2016-12-19 7:23 UTC (permalink / raw)
To: Maxim Uvarov
Cc: mark.rutland, geoff, kexec, james.morse, Dave Young, linux-arm-kernel
On Monday 19 December 2016 12:51 PM, Maxim Uvarov wrote:
>> +
>> > +static void craete_block_entry(unsigned long *tbl, unsigned long flags,
> typo in name
>
Thanks.
Will fix.
~Pratyush
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 22+ messages in thread
* [PATCH V2 0/2] kexec-tools: arm64: Enable D-cache in purgatory
2016-12-19 7:13 ` Pratyush Anand
@ 2017-01-06 3:31 ` Pratyush Anand
-1 siblings, 0 replies; 22+ messages in thread
From: Pratyush Anand @ 2017-01-06 3:31 UTC (permalink / raw)
To: linux-arm-kernel
Hi James and All,
Any feedback/review comment on it?
~Pratyush
On Monday 19 December 2016 12:43 PM, Pratyush Anand wrote:
> It takes more that 2 minutes to verify SHA in purgatory when vmlinuz image
> is around 13MB and initramfs is around 30MB. It takes more than 20 second
> even when we have -O2 optimization enabled. However, if dcache is enabled
> during purgatory execution then, it takes just a second in SHA
> verification.
>
> Therefore, these patches adds support for dcache enabling facility during
> purgatory execution.
>
> Although I have simplified the logic a bit now, however I understand that
> there are reservations for introducing this complexity for gaining few
> seconding of execution time during kexec or crash reboot. But, I believe
> if d-cache enabling code is stable enough then there should not be any
> hindrances to accept it. So, please give it a try with your platform and
> let me know if you see any issue or it does not work. I am still open to
> improve it further if needed.
>
> Changes since V1:
> - Moved page table creation logic from purgatory to kexec code.
> - Only 4K page table is supported, with 48 bit VA and 2M block size
> - if platform supports a 4K page size, then D-cache is always
> enabled now.
>
> Pratyush Anand (2):
> kexec: arm64: create identity page table to be used in purgatory
> arm64: enable d-cache support during purgatory sha verification
>
> kexec/arch/arm64/kexec-arm64.c | 152 ++++++++++++++++++
> purgatory/arch/arm64/Makefile | 1 +
> purgatory/arch/arm64/cache.S | 281 +++++++++++++++++++++++++++++++++
> purgatory/arch/arm64/purgatory-arm64.c | 5 +
> 4 files changed, 439 insertions(+)
> create mode 100644 purgatory/arch/arm64/cache.S
>
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH V2 0/2] kexec-tools: arm64: Enable D-cache in purgatory
@ 2017-01-06 3:31 ` Pratyush Anand
0 siblings, 0 replies; 22+ messages in thread
From: Pratyush Anand @ 2017-01-06 3:31 UTC (permalink / raw)
To: kexec, geoff, james.morse; +Cc: mark.rutland, dyoung, linux-arm-kernel
Hi James and All,
Any feedback/review comment on it?
~Pratyush
On Monday 19 December 2016 12:43 PM, Pratyush Anand wrote:
> It takes more that 2 minutes to verify SHA in purgatory when vmlinuz image
> is around 13MB and initramfs is around 30MB. It takes more than 20 second
> even when we have -O2 optimization enabled. However, if dcache is enabled
> during purgatory execution then, it takes just a second in SHA
> verification.
>
> Therefore, these patches adds support for dcache enabling facility during
> purgatory execution.
>
> Although I have simplified the logic a bit now, however I understand that
> there are reservations for introducing this complexity for gaining few
> seconding of execution time during kexec or crash reboot. But, I believe
> if d-cache enabling code is stable enough then there should not be any
> hindrances to accept it. So, please give it a try with your platform and
> let me know if you see any issue or it does not work. I am still open to
> improve it further if needed.
>
> Changes since V1:
> - Moved page table creation logic from purgatory to kexec code.
> - Only 4K page table is supported, with 48 bit VA and 2M block size
> - if platform supports a 4K page size, then D-cache is always
> enabled now.
>
> Pratyush Anand (2):
> kexec: arm64: create identity page table to be used in purgatory
> arm64: enable d-cache support during purgatory sha verification
>
> kexec/arch/arm64/kexec-arm64.c | 152 ++++++++++++++++++
> purgatory/arch/arm64/Makefile | 1 +
> purgatory/arch/arm64/cache.S | 281 +++++++++++++++++++++++++++++++++
> purgatory/arch/arm64/purgatory-arm64.c | 5 +
> 4 files changed, 439 insertions(+)
> create mode 100644 purgatory/arch/arm64/cache.S
>
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 22+ messages in thread
* [PATCH V2 0/2] kexec-tools: arm64: Enable D-cache in purgatory
2017-01-06 3:31 ` Pratyush Anand
@ 2017-01-10 14:11 ` James Morse
-1 siblings, 0 replies; 22+ messages in thread
From: James Morse @ 2017-01-10 14:11 UTC (permalink / raw)
To: linux-arm-kernel
Hi Pratyush,
On 06/01/17 03:31, Pratyush Anand wrote:
> Any feedback/review comment on it?
I started going through this last week, I hope to get back to it later this
week. (I also need to learn/remember how some of the kexec-tools stuff works).
Thanks,
James
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH V2 0/2] kexec-tools: arm64: Enable D-cache in purgatory
@ 2017-01-10 14:11 ` James Morse
0 siblings, 0 replies; 22+ messages in thread
From: James Morse @ 2017-01-10 14:11 UTC (permalink / raw)
To: Pratyush Anand; +Cc: geoff, mark.rutland, dyoung, kexec, linux-arm-kernel
Hi Pratyush,
On 06/01/17 03:31, Pratyush Anand wrote:
> Any feedback/review comment on it?
I started going through this last week, I hope to get back to it later this
week. (I also need to learn/remember how some of the kexec-tools stuff works).
Thanks,
James
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 22+ messages in thread
* [PATCH V2 1/2] kexec: arm64: create identity page table to be used in purgatory
2016-12-19 7:13 ` Pratyush Anand
@ 2017-01-17 17:25 ` James Morse
-1 siblings, 0 replies; 22+ messages in thread
From: James Morse @ 2017-01-17 17:25 UTC (permalink / raw)
To: linux-arm-kernel
Hi Pratyush,
On 19/12/16 07:13, Pratyush Anand wrote:
> Purgatory sha verification is very slow when D-cache is not enabled there.
> We need to enable MMU as well to enable D-Cache.Therefore,we need to an
> identity mapped page table in purgatory.
>
> Since debugging is very difficult in purgatory therefore we prefer to do as
> much work as possible in kexec.
>
> This patch prepares page table for purgatory in advance. We support only 4K
> page table,because it will be available on most of the platform. This page
> table is passed to the purgatory as a new segment.
>
> VA bit is fixed as 48, page table level is 3 where 3rd level page table
> contains 2M block entries.
> diff --git a/kexec/arch/arm64/kexec-arm64.c b/kexec/arch/arm64/kexec-arm64.c
> index 04fd3968bb52..c2c8ff1b6940 100644
> --- a/kexec/arch/arm64/kexec-arm64.c
> +++ b/kexec/arch/arm64/kexec-arm64.c
> @@ -24,6 +24,45 @@
> #include "kexec-syscall.h"
> #include "arch/options.h"
>
> +/*
> + * kexec creates identity page table to be used in purgatory so that
> + * dcache verification becomes faster.
> + *
> + * These are the definitions to be used by page table creation routine.
> + *
> + * Only 4K page table, 3 level, 2M block mapping, 48bit VA is supported
> + */
> +#define PGDIR_SHIFT 39
> +#define PUD_SHIFT 30
> +#define PMD_SHIFT 21
> +#define PTRS_PER_PGD 0x1FF
> +#define PTRS_PER_PUD 0x1FF
> +#define PTRS_PER_PMD 0x1FF
Aren't these 0x200 for 4K pages in the kernel? It looks like you use them as a
mask instead.
> +#define PMD_TYPE_TABLE (3UL << 0)
> +#define PMD_TYPE_SECT (1UL << 0)
> +#define PMD_SECT_AF (1UL << 10)
> +#define PMD_ATTRINDX(t) ((unsigned long)(t) << 2)
> +#define MT_NORMAL 4
This needs to correspond to the part of MAIR that describes the memory type for
'normal'. You define MT_NORMAL again in the next patch, it would be better to
share the definition so they can't be different. (I don't see why you can't use 0!)
> +#define PMD_FLAGS_NORMAL (PMD_TYPE_SECT | PMD_SECT_AF)
> +#define MMU_FLAGS_NORMAL (PMD_ATTRINDX(MT_NORMAL) | PMD_FLAGS_NORMAL)
The SH and AP bits are left as zero, which means non-shareable, read/writeable,
(which I think is fine).
> +#define SECTION_SIZE (2 * 1024 * 1024)
> +#define PAGE_SIZE (4 * 1024)
> +/* Since we are using 3 level of page tables, therefore minimum number of
> + * table will be 3. Most likely we will never need more than 3. Each entry
> + * in level 3 page table can map 2MB memory area. Thus a level 3 page table
> + * indexed by bit 29:21 can map a total of 1G memory area. Therefore, if
> + * any segment crosses 1G boundary, then we will need one more level 3
> + * table. Similarly, level 2 page table indexed by bit 38:30 can map a
> + * total of 512G memory area. If segment addresses are more than 512G apart
> + * then we will need two more table for each such block. We do not expect
> + * any memory segment to cross 512G boundary, however if we will ever wish
> + * to support uart debugging in purgatory then that might cross the
> + * boundary and therefore additional 2 more table space. Thus we will need
> + * maximum of 6 table space.
Surely we only need 6 page_size table entries if we support uart debugging,
which your 'if we ever' suggests we don't. So surely we only need 3, and a
comment that this needs expanding to 6 if we need to map two distinct areas.
> + */
> +#define MAX_PGTBLE_SZ (6 * 4096)
> +static int next_tbl_cnt = 1;
> +
> /* Global varables the core kexec routines expect. */
>
> unsigned char reuse_initrd;
> @@ -316,6 +355,117 @@ unsigned long arm64_locate_kernel_segment(struct kexec_info *info)
> return hole;
> }
>
> +static unsigned long *create_table_entry(unsigned long *pgtbl_buf,
> + unsigned long pgtbl_mem, unsigned long *tbl,
> + unsigned long virt, int shift,
> + unsigned long ptrs)
> +{
> + unsigned long index, desc, offset;
> +
> + index = (virt >> shift) & ptrs;
> + /* check if we have allocated a table already for this index */
> + if (tbl[index]) {
> + /*
> + * table index will have entry as per purgatory page table
> + * memory. Find out corresponding buffer address of table.
> + */
> + desc = tbl[index] & ~3UL;
> + offset = desc - pgtbl_mem;
wait .. no .. pgtbl_mem is also a guest physical address, so this is fine... its
not obvious at first glance! You could do with a typedef to make it clear which
addresses are the guests (pgtable_mem) and which are the hosts (pgtable_buf).
Something like phys_addr_t?
> + return &pgtbl_buf[offset >> 3];
> + }
> +
> + /*
> + * Always write page table content as per page table memory allocated
> + * for purgaory area, but return corresponding buffer area alloced
Nit: purgatory, allocated,
> + * in kexec
> + */
> + if (next_tbl_cnt > 5)
> + die("%s: No more memory for page table\n", __func__);
die()? With a bit of juggling can't we return an error so we never try to enable
the MMU+dcache instead?
> +
> + tbl[index] = (pgtbl_mem + PAGE_SIZE * next_tbl_cnt) | PMD_TYPE_TABLE;
> +
> + return &pgtbl_buf[(next_tbl_cnt++ * PAGE_SIZE) >> 3];
> +}
> +
> +static void craete_block_entry(unsigned long *tbl, unsigned long flags,
> + unsigned long phys, unsigned long virt)
Why have separate phys and virt parameters if all this ever does is idmap?
> +{
> + unsigned long index;
> + unsigned long desc;
> +
> + index = (virt >> PMD_SHIFT) & PTRS_PER_PMD;
Copying the pmd_index() macro would make this clearer.
> + desc = (phys >> PMD_SHIFT) << PMD_SHIFT;
Looks like you wanted a PMD_MASK.
> + desc |= flags;
> + tbl[index] = desc;
> +}
> +
> +static void create_identity_entry(unsigned long *pgtbl_buf,
> + unsigned long pgtbl_mem, unsigned long virt,
> + unsigned long flags)
> +{
> + unsigned long *tbl = pgtbl_buf;
> +
> + tbl = create_table_entry(pgtbl_buf, pgtbl_mem, tbl, virt,
> + PGDIR_SHIFT, PTRS_PER_PGD);
> + tbl = create_table_entry(pgtbl_buf, pgtbl_mem, tbl, virt,
> + PUD_SHIFT, PTRS_PER_PUD);
> + craete_block_entry(tbl, flags, virt, virt);
Nit: create
> +}
> +
> +/**
> + * arm64_create_pgtbl_segment - Create page table segments to be used by
> + * purgatory. Page table will have entries to access memory area of all
> + * those segments which becomes part of sha verification in purgatory.
> + * Additionaly, we also create page table for purgatory segment as well.
Nit: additionally,
> + */
> +
> +static int arm64_create_pgtbl_segment(struct kexec_info *info,
> + unsigned long hole_min, unsigned long hole_max)
> +{
> + unsigned long *pgtbl_buf;
> + int i;
> + unsigned long mstart, mend, pgtbl_mem;
> + unsigned long purgatory_base, purgatory_len;
> +
> + pgtbl_buf = xmalloc(MAX_PGTBLE_SZ);
> + memset(pgtbl_buf, 0, MAX_PGTBLE_SZ);
> + pgtbl_mem = add_buffer_phys_virt(info, pgtbl_buf, MAX_PGTBLE_SZ,
> + MAX_PGTBLE_SZ, PAGE_SIZE, hole_min, hole_max, 1, 0);
I want to check what this does, but this all looks like it is doing the right thing.
> + for (i = 0; i < info->nr_segments; i++) {
> + if (info->segment[i].mem == (void *)info->rhdr.rel_addr) {
> + purgatory_base = (unsigned long)info->segment[i].mem;
> + purgatory_len = info->segment[i].memsz;
> + }
> + mstart = (unsigned long)info->segment[i].mem;
> + mend = mstart + info->segment[i].memsz;
> + mstart &= ~(SECTION_SIZE - 1);
> + while (mstart < mend) {
> + create_identity_entry(pgtbl_buf, pgtbl_mem,
> + mstart, MMU_FLAGS_NORMAL);
> + mstart += SECTION_SIZE;
> + }
> + }
Thanks,
James
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH V2 1/2] kexec: arm64: create identity page table to be used in purgatory
@ 2017-01-17 17:25 ` James Morse
0 siblings, 0 replies; 22+ messages in thread
From: James Morse @ 2017-01-17 17:25 UTC (permalink / raw)
To: Pratyush Anand; +Cc: geoff, mark.rutland, dyoung, kexec, linux-arm-kernel
Hi Pratyush,
On 19/12/16 07:13, Pratyush Anand wrote:
> Purgatory sha verification is very slow when D-cache is not enabled there.
> We need to enable MMU as well to enable D-Cache.Therefore,we need to an
> identity mapped page table in purgatory.
>
> Since debugging is very difficult in purgatory therefore we prefer to do as
> much work as possible in kexec.
>
> This patch prepares page table for purgatory in advance. We support only 4K
> page table,because it will be available on most of the platform. This page
> table is passed to the purgatory as a new segment.
>
> VA bit is fixed as 48, page table level is 3 where 3rd level page table
> contains 2M block entries.
> diff --git a/kexec/arch/arm64/kexec-arm64.c b/kexec/arch/arm64/kexec-arm64.c
> index 04fd3968bb52..c2c8ff1b6940 100644
> --- a/kexec/arch/arm64/kexec-arm64.c
> +++ b/kexec/arch/arm64/kexec-arm64.c
> @@ -24,6 +24,45 @@
> #include "kexec-syscall.h"
> #include "arch/options.h"
>
> +/*
> + * kexec creates identity page table to be used in purgatory so that
> + * dcache verification becomes faster.
> + *
> + * These are the definitions to be used by page table creation routine.
> + *
> + * Only 4K page table, 3 level, 2M block mapping, 48bit VA is supported
> + */
> +#define PGDIR_SHIFT 39
> +#define PUD_SHIFT 30
> +#define PMD_SHIFT 21
> +#define PTRS_PER_PGD 0x1FF
> +#define PTRS_PER_PUD 0x1FF
> +#define PTRS_PER_PMD 0x1FF
Aren't these 0x200 for 4K pages in the kernel? It looks like you use them as a
mask instead.
> +#define PMD_TYPE_TABLE (3UL << 0)
> +#define PMD_TYPE_SECT (1UL << 0)
> +#define PMD_SECT_AF (1UL << 10)
> +#define PMD_ATTRINDX(t) ((unsigned long)(t) << 2)
> +#define MT_NORMAL 4
This needs to correspond to the part of MAIR that describes the memory type for
'normal'. You define MT_NORMAL again in the next patch, it would be better to
share the definition so they can't be different. (I don't see why you can't use 0!)
> +#define PMD_FLAGS_NORMAL (PMD_TYPE_SECT | PMD_SECT_AF)
> +#define MMU_FLAGS_NORMAL (PMD_ATTRINDX(MT_NORMAL) | PMD_FLAGS_NORMAL)
The SH and AP bits are left as zero, which means non-shareable, read/writeable,
(which I think is fine).
> +#define SECTION_SIZE (2 * 1024 * 1024)
> +#define PAGE_SIZE (4 * 1024)
> +/* Since we are using 3 level of page tables, therefore minimum number of
> + * table will be 3. Most likely we will never need more than 3. Each entry
> + * in level 3 page table can map 2MB memory area. Thus a level 3 page table
> + * indexed by bit 29:21 can map a total of 1G memory area. Therefore, if
> + * any segment crosses 1G boundary, then we will need one more level 3
> + * table. Similarly, level 2 page table indexed by bit 38:30 can map a
> + * total of 512G memory area. If segment addresses are more than 512G apart
> + * then we will need two more table for each such block. We do not expect
> + * any memory segment to cross 512G boundary, however if we will ever wish
> + * to support uart debugging in purgatory then that might cross the
> + * boundary and therefore additional 2 more table space. Thus we will need
> + * maximum of 6 table space.
Surely we only need 6 page_size table entries if we support uart debugging,
which your 'if we ever' suggests we don't. So surely we only need 3, and a
comment that this needs expanding to 6 if we need to map two distinct areas.
> + */
> +#define MAX_PGTBLE_SZ (6 * 4096)
> +static int next_tbl_cnt = 1;
> +
> /* Global varables the core kexec routines expect. */
>
> unsigned char reuse_initrd;
> @@ -316,6 +355,117 @@ unsigned long arm64_locate_kernel_segment(struct kexec_info *info)
> return hole;
> }
>
> +static unsigned long *create_table_entry(unsigned long *pgtbl_buf,
> + unsigned long pgtbl_mem, unsigned long *tbl,
> + unsigned long virt, int shift,
> + unsigned long ptrs)
> +{
> + unsigned long index, desc, offset;
> +
> + index = (virt >> shift) & ptrs;
> + /* check if we have allocated a table already for this index */
> + if (tbl[index]) {
> + /*
> + * table index will have entry as per purgatory page table
> + * memory. Find out corresponding buffer address of table.
> + */
> + desc = tbl[index] & ~3UL;
> + offset = desc - pgtbl_mem;
wait .. no .. pgtbl_mem is also a guest physical address, so this is fine... its
not obvious at first glance! You could do with a typedef to make it clear which
addresses are the guests (pgtable_mem) and which are the hosts (pgtable_buf).
Something like phys_addr_t?
> + return &pgtbl_buf[offset >> 3];
> + }
> +
> + /*
> + * Always write page table content as per page table memory allocated
> + * for purgaory area, but return corresponding buffer area alloced
Nit: purgatory, allocated,
> + * in kexec
> + */
> + if (next_tbl_cnt > 5)
> + die("%s: No more memory for page table\n", __func__);
die()? With a bit of juggling can't we return an error so we never try to enable
the MMU+dcache instead?
> +
> + tbl[index] = (pgtbl_mem + PAGE_SIZE * next_tbl_cnt) | PMD_TYPE_TABLE;
> +
> + return &pgtbl_buf[(next_tbl_cnt++ * PAGE_SIZE) >> 3];
> +}
> +
> +static void craete_block_entry(unsigned long *tbl, unsigned long flags,
> + unsigned long phys, unsigned long virt)
Why have separate phys and virt parameters if all this ever does is idmap?
> +{
> + unsigned long index;
> + unsigned long desc;
> +
> + index = (virt >> PMD_SHIFT) & PTRS_PER_PMD;
Copying the pmd_index() macro would make this clearer.
> + desc = (phys >> PMD_SHIFT) << PMD_SHIFT;
Looks like you wanted a PMD_MASK.
> + desc |= flags;
> + tbl[index] = desc;
> +}
> +
> +static void create_identity_entry(unsigned long *pgtbl_buf,
> + unsigned long pgtbl_mem, unsigned long virt,
> + unsigned long flags)
> +{
> + unsigned long *tbl = pgtbl_buf;
> +
> + tbl = create_table_entry(pgtbl_buf, pgtbl_mem, tbl, virt,
> + PGDIR_SHIFT, PTRS_PER_PGD);
> + tbl = create_table_entry(pgtbl_buf, pgtbl_mem, tbl, virt,
> + PUD_SHIFT, PTRS_PER_PUD);
> + craete_block_entry(tbl, flags, virt, virt);
Nit: create
> +}
> +
> +/**
> + * arm64_create_pgtbl_segment - Create page table segments to be used by
> + * purgatory. Page table will have entries to access memory area of all
> + * those segments which becomes part of sha verification in purgatory.
> + * Additionaly, we also create page table for purgatory segment as well.
Nit: additionally,
> + */
> +
> +static int arm64_create_pgtbl_segment(struct kexec_info *info,
> + unsigned long hole_min, unsigned long hole_max)
> +{
> + unsigned long *pgtbl_buf;
> + int i;
> + unsigned long mstart, mend, pgtbl_mem;
> + unsigned long purgatory_base, purgatory_len;
> +
> + pgtbl_buf = xmalloc(MAX_PGTBLE_SZ);
> + memset(pgtbl_buf, 0, MAX_PGTBLE_SZ);
> + pgtbl_mem = add_buffer_phys_virt(info, pgtbl_buf, MAX_PGTBLE_SZ,
> + MAX_PGTBLE_SZ, PAGE_SIZE, hole_min, hole_max, 1, 0);
I want to check what this does, but this all looks like it is doing the right thing.
> + for (i = 0; i < info->nr_segments; i++) {
> + if (info->segment[i].mem == (void *)info->rhdr.rel_addr) {
> + purgatory_base = (unsigned long)info->segment[i].mem;
> + purgatory_len = info->segment[i].memsz;
> + }
> + mstart = (unsigned long)info->segment[i].mem;
> + mend = mstart + info->segment[i].memsz;
> + mstart &= ~(SECTION_SIZE - 1);
> + while (mstart < mend) {
> + create_identity_entry(pgtbl_buf, pgtbl_mem,
> + mstart, MMU_FLAGS_NORMAL);
> + mstart += SECTION_SIZE;
> + }
> + }
Thanks,
James
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 22+ messages in thread
* [PATCH V2 1/2] kexec: arm64: create identity page table to be used in purgatory
2017-01-17 17:25 ` James Morse
@ 2017-01-18 7:43 ` Pratyush Anand
-1 siblings, 0 replies; 22+ messages in thread
From: Pratyush Anand @ 2017-01-18 7:43 UTC (permalink / raw)
To: linux-arm-kernel
Hi James,
Thanks for your review.
On Tuesday 17 January 2017 10:55 PM, James Morse wrote:
> Hi Pratyush,
>
> On 19/12/16 07:13, Pratyush Anand wrote:
>> Purgatory sha verification is very slow when D-cache is not enabled there.
>> We need to enable MMU as well to enable D-Cache.Therefore,we need to an
>> identity mapped page table in purgatory.
>>
>> Since debugging is very difficult in purgatory therefore we prefer to do as
>> much work as possible in kexec.
>>
>> This patch prepares page table for purgatory in advance. We support only 4K
>> page table,because it will be available on most of the platform. This page
>> table is passed to the purgatory as a new segment.
>>
>> VA bit is fixed as 48, page table level is 3 where 3rd level page table
>> contains 2M block entries.
>
>> diff --git a/kexec/arch/arm64/kexec-arm64.c b/kexec/arch/arm64/kexec-arm64.c
>> index 04fd3968bb52..c2c8ff1b6940 100644
>> --- a/kexec/arch/arm64/kexec-arm64.c
>> +++ b/kexec/arch/arm64/kexec-arm64.c
>> @@ -24,6 +24,45 @@
>> #include "kexec-syscall.h"
>> #include "arch/options.h"
>>
>> +/*
>> + * kexec creates identity page table to be used in purgatory so that
>> + * dcache verification becomes faster.
>> + *
>> + * These are the definitions to be used by page table creation routine.
>> + *
>> + * Only 4K page table, 3 level, 2M block mapping, 48bit VA is supported
>> + */
>> +#define PGDIR_SHIFT 39
>> +#define PUD_SHIFT 30
>> +#define PMD_SHIFT 21
>> +#define PTRS_PER_PGD 0x1FF
>> +#define PTRS_PER_PUD 0x1FF
>> +#define PTRS_PER_PMD 0x1FF
>
> Aren't these 0x200 for 4K pages in the kernel? It looks like you use them as a
> mask instead.
>
will use definitions as in kernel.
>
>> +#define PMD_TYPE_TABLE (3UL << 0)
>> +#define PMD_TYPE_SECT (1UL << 0)
>> +#define PMD_SECT_AF (1UL << 10)
>> +#define PMD_ATTRINDX(t) ((unsigned long)(t) << 2)
>
>> +#define MT_NORMAL 4
>
> This needs to correspond to the part of MAIR that describes the memory type for
> 'normal'. You define MT_NORMAL again in the next patch, it would be better to
> share the definition so they can't be different. (I don't see why you can't use 0!)
Hummm...Had thought to share the definition, but inclusion of header
file into purgatory code looked like ugly. But I see
purgatory/purgatory.c is including "../kexec/kexec-sha256.h". So,
probably I can do that similarly.
Yes, can use 0 as well, as there is no other memory type now.
>
>
>> +#define PMD_FLAGS_NORMAL (PMD_TYPE_SECT | PMD_SECT_AF)
>> +#define MMU_FLAGS_NORMAL (PMD_ATTRINDX(MT_NORMAL) | PMD_FLAGS_NORMAL)
>
> The SH and AP bits are left as zero, which means non-shareable, read/writeable,
> (which I think is fine).
>
>
>> +#define SECTION_SIZE (2 * 1024 * 1024)
>> +#define PAGE_SIZE (4 * 1024)
>> +/* Since we are using 3 level of page tables, therefore minimum number of
>> + * table will be 3. Most likely we will never need more than 3. Each entry
>> + * in level 3 page table can map 2MB memory area. Thus a level 3 page table
>> + * indexed by bit 29:21 can map a total of 1G memory area. Therefore, if
>> + * any segment crosses 1G boundary, then we will need one more level 3
>> + * table. Similarly, level 2 page table indexed by bit 38:30 can map a
>> + * total of 512G memory area. If segment addresses are more than 512G apart
>> + * then we will need two more table for each such block. We do not expect
>> + * any memory segment to cross 512G boundary, however if we will ever wish
>> + * to support uart debugging in purgatory then that might cross the
>> + * boundary and therefore additional 2 more table space. Thus we will need
>> + * maximum of 6 table space.
>
> Surely we only need 6 page_size table entries if we support uart debugging,
> which your 'if we ever' suggests we don't. So surely we only need 3, and a
> comment that this needs expanding to 6 if we need to map two distinct areas.
>
OK, will use 3 now and write comments accordingly.
>
>> + */
>> +#define MAX_PGTBLE_SZ (6 * 4096)
>> +static int next_tbl_cnt = 1;
>> +
>> /* Global varables the core kexec routines expect. */
>>
>> unsigned char reuse_initrd;
>> @@ -316,6 +355,117 @@ unsigned long arm64_locate_kernel_segment(struct kexec_info *info)
>> return hole;
>> }
>>
>> +static unsigned long *create_table_entry(unsigned long *pgtbl_buf,
>> + unsigned long pgtbl_mem, unsigned long *tbl,
>> + unsigned long virt, int shift,
>> + unsigned long ptrs)
>> +{
>> + unsigned long index, desc, offset;
>> +
>> + index = (virt >> shift) & ptrs;
>> + /* check if we have allocated a table already for this index */
>> + if (tbl[index]) {
>> + /*
>> + * table index will have entry as per purgatory page table
>> + * memory. Find out corresponding buffer address of table.
>> + */
>> + desc = tbl[index] & ~3UL;
>> + offset = desc - pgtbl_mem;
>
> wait .. no .. pgtbl_mem is also a guest physical address, so this is fine... its
> not obvious at first glance! You could do with a typedef to make it clear which
> addresses are the guests (pgtable_mem) and which are the hosts (pgtable_buf).
> Something like phys_addr_t?
so may be host_addr_t and guest_addr_t??
>
>
>> + return &pgtbl_buf[offset >> 3];
>> + }
>> +
>> + /*
>> + * Always write page table content as per page table memory allocated
>> + * for purgaory area, but return corresponding buffer area alloced
>
> Nit: purgatory, allocated,
ok.
>
>> + * in kexec
>> + */
>> + if (next_tbl_cnt > 5)
>> + die("%s: No more memory for page table\n", __func__);
>
> die()? With a bit of juggling can't we return an error so we never try to enable
> the MMU+dcache instead?
>
OK. can do that.
>
>> +
>> + tbl[index] = (pgtbl_mem + PAGE_SIZE * next_tbl_cnt) | PMD_TYPE_TABLE;
>> +
>> + return &pgtbl_buf[(next_tbl_cnt++ * PAGE_SIZE) >> 3];
>> +}
>> +
>> +static void craete_block_entry(unsigned long *tbl, unsigned long flags,
>> + unsigned long phys, unsigned long virt)
>
> Why have separate phys and virt parameters if all this ever does is idmap?
Agreed.
>
>
>> +{
>> + unsigned long index;
>> + unsigned long desc;
>> +
>> + index = (virt >> PMD_SHIFT) & PTRS_PER_PMD;
>
> Copying the pmd_index() macro would make this clearer.
Right.
>
>
>> + desc = (phys >> PMD_SHIFT) << PMD_SHIFT;
>
> Looks like you wanted a PMD_MASK.
Right.
>
>
>> + desc |= flags;
>> + tbl[index] = desc;
>> +}
>> +
>> +static void create_identity_entry(unsigned long *pgtbl_buf,
>> + unsigned long pgtbl_mem, unsigned long virt,
>> + unsigned long flags)
>> +{
>> + unsigned long *tbl = pgtbl_buf;
>> +
>> + tbl = create_table_entry(pgtbl_buf, pgtbl_mem, tbl, virt,
>> + PGDIR_SHIFT, PTRS_PER_PGD);
>> + tbl = create_table_entry(pgtbl_buf, pgtbl_mem, tbl, virt,
>> + PUD_SHIFT, PTRS_PER_PUD);
>> + craete_block_entry(tbl, flags, virt, virt);
>
> Nit: create
Ok.
>
>> +}
>> +
>> +/**
>> + * arm64_create_pgtbl_segment - Create page table segments to be used by
>> + * purgatory. Page table will have entries to access memory area of all
>> + * those segments which becomes part of sha verification in purgatory.
>> + * Additionaly, we also create page table for purgatory segment as well.
>
> Nit: additionally,
Ok.
>
>> + */
>> +
>> +static int arm64_create_pgtbl_segment(struct kexec_info *info,
>> + unsigned long hole_min, unsigned long hole_max)
>> +{
>> + unsigned long *pgtbl_buf;
>> + int i;
>> + unsigned long mstart, mend, pgtbl_mem;
>> + unsigned long purgatory_base, purgatory_len;
>> +
>> + pgtbl_buf = xmalloc(MAX_PGTBLE_SZ);
>> + memset(pgtbl_buf, 0, MAX_PGTBLE_SZ);
>
>> + pgtbl_mem = add_buffer_phys_virt(info, pgtbl_buf, MAX_PGTBLE_SZ,
>> + MAX_PGTBLE_SZ, PAGE_SIZE, hole_min, hole_max, 1, 0);
>
> I want to check what this does, but this all looks like it is doing the right thing.
>
>
>> + for (i = 0; i < info->nr_segments; i++) {
>> + if (info->segment[i].mem == (void *)info->rhdr.rel_addr) {
>> + purgatory_base = (unsigned long)info->segment[i].mem;
>> + purgatory_len = info->segment[i].memsz;
>> + }
>> + mstart = (unsigned long)info->segment[i].mem;
>> + mend = mstart + info->segment[i].memsz;
>> + mstart &= ~(SECTION_SIZE - 1);
>> + while (mstart < mend) {
>> + create_identity_entry(pgtbl_buf, pgtbl_mem,
>> + mstart, MMU_FLAGS_NORMAL);
>> + mstart += SECTION_SIZE;
>> + }
>> + }
>
~Pratyush
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH V2 1/2] kexec: arm64: create identity page table to be used in purgatory
@ 2017-01-18 7:43 ` Pratyush Anand
0 siblings, 0 replies; 22+ messages in thread
From: Pratyush Anand @ 2017-01-18 7:43 UTC (permalink / raw)
To: James Morse; +Cc: geoff, mark.rutland, dyoung, kexec, linux-arm-kernel
Hi James,
Thanks for your review.
On Tuesday 17 January 2017 10:55 PM, James Morse wrote:
> Hi Pratyush,
>
> On 19/12/16 07:13, Pratyush Anand wrote:
>> Purgatory sha verification is very slow when D-cache is not enabled there.
>> We need to enable MMU as well to enable D-Cache.Therefore,we need to an
>> identity mapped page table in purgatory.
>>
>> Since debugging is very difficult in purgatory therefore we prefer to do as
>> much work as possible in kexec.
>>
>> This patch prepares page table for purgatory in advance. We support only 4K
>> page table,because it will be available on most of the platform. This page
>> table is passed to the purgatory as a new segment.
>>
>> VA bit is fixed as 48, page table level is 3 where 3rd level page table
>> contains 2M block entries.
>
>> diff --git a/kexec/arch/arm64/kexec-arm64.c b/kexec/arch/arm64/kexec-arm64.c
>> index 04fd3968bb52..c2c8ff1b6940 100644
>> --- a/kexec/arch/arm64/kexec-arm64.c
>> +++ b/kexec/arch/arm64/kexec-arm64.c
>> @@ -24,6 +24,45 @@
>> #include "kexec-syscall.h"
>> #include "arch/options.h"
>>
>> +/*
>> + * kexec creates identity page table to be used in purgatory so that
>> + * dcache verification becomes faster.
>> + *
>> + * These are the definitions to be used by page table creation routine.
>> + *
>> + * Only 4K page table, 3 level, 2M block mapping, 48bit VA is supported
>> + */
>> +#define PGDIR_SHIFT 39
>> +#define PUD_SHIFT 30
>> +#define PMD_SHIFT 21
>> +#define PTRS_PER_PGD 0x1FF
>> +#define PTRS_PER_PUD 0x1FF
>> +#define PTRS_PER_PMD 0x1FF
>
> Aren't these 0x200 for 4K pages in the kernel? It looks like you use them as a
> mask instead.
>
will use definitions as in kernel.
>
>> +#define PMD_TYPE_TABLE (3UL << 0)
>> +#define PMD_TYPE_SECT (1UL << 0)
>> +#define PMD_SECT_AF (1UL << 10)
>> +#define PMD_ATTRINDX(t) ((unsigned long)(t) << 2)
>
>> +#define MT_NORMAL 4
>
> This needs to correspond to the part of MAIR that describes the memory type for
> 'normal'. You define MT_NORMAL again in the next patch, it would be better to
> share the definition so they can't be different. (I don't see why you can't use 0!)
Hummm...Had thought to share the definition, but inclusion of header
file into purgatory code looked like ugly. But I see
purgatory/purgatory.c is including "../kexec/kexec-sha256.h". So,
probably I can do that similarly.
Yes, can use 0 as well, as there is no other memory type now.
>
>
>> +#define PMD_FLAGS_NORMAL (PMD_TYPE_SECT | PMD_SECT_AF)
>> +#define MMU_FLAGS_NORMAL (PMD_ATTRINDX(MT_NORMAL) | PMD_FLAGS_NORMAL)
>
> The SH and AP bits are left as zero, which means non-shareable, read/writeable,
> (which I think is fine).
>
>
>> +#define SECTION_SIZE (2 * 1024 * 1024)
>> +#define PAGE_SIZE (4 * 1024)
>> +/* Since we are using 3 level of page tables, therefore minimum number of
>> + * table will be 3. Most likely we will never need more than 3. Each entry
>> + * in level 3 page table can map 2MB memory area. Thus a level 3 page table
>> + * indexed by bit 29:21 can map a total of 1G memory area. Therefore, if
>> + * any segment crosses 1G boundary, then we will need one more level 3
>> + * table. Similarly, level 2 page table indexed by bit 38:30 can map a
>> + * total of 512G memory area. If segment addresses are more than 512G apart
>> + * then we will need two more table for each such block. We do not expect
>> + * any memory segment to cross 512G boundary, however if we will ever wish
>> + * to support uart debugging in purgatory then that might cross the
>> + * boundary and therefore additional 2 more table space. Thus we will need
>> + * maximum of 6 table space.
>
> Surely we only need 6 page_size table entries if we support uart debugging,
> which your 'if we ever' suggests we don't. So surely we only need 3, and a
> comment that this needs expanding to 6 if we need to map two distinct areas.
>
OK, will use 3 now and write comments accordingly.
>
>> + */
>> +#define MAX_PGTBLE_SZ (6 * 4096)
>> +static int next_tbl_cnt = 1;
>> +
>> /* Global varables the core kexec routines expect. */
>>
>> unsigned char reuse_initrd;
>> @@ -316,6 +355,117 @@ unsigned long arm64_locate_kernel_segment(struct kexec_info *info)
>> return hole;
>> }
>>
>> +static unsigned long *create_table_entry(unsigned long *pgtbl_buf,
>> + unsigned long pgtbl_mem, unsigned long *tbl,
>> + unsigned long virt, int shift,
>> + unsigned long ptrs)
>> +{
>> + unsigned long index, desc, offset;
>> +
>> + index = (virt >> shift) & ptrs;
>> + /* check if we have allocated a table already for this index */
>> + if (tbl[index]) {
>> + /*
>> + * table index will have entry as per purgatory page table
>> + * memory. Find out corresponding buffer address of table.
>> + */
>> + desc = tbl[index] & ~3UL;
>> + offset = desc - pgtbl_mem;
>
> wait .. no .. pgtbl_mem is also a guest physical address, so this is fine... its
> not obvious at first glance! You could do with a typedef to make it clear which
> addresses are the guests (pgtable_mem) and which are the hosts (pgtable_buf).
> Something like phys_addr_t?
so may be host_addr_t and guest_addr_t??
>
>
>> + return &pgtbl_buf[offset >> 3];
>> + }
>> +
>> + /*
>> + * Always write page table content as per page table memory allocated
>> + * for purgaory area, but return corresponding buffer area alloced
>
> Nit: purgatory, allocated,
ok.
>
>> + * in kexec
>> + */
>> + if (next_tbl_cnt > 5)
>> + die("%s: No more memory for page table\n", __func__);
>
> die()? With a bit of juggling can't we return an error so we never try to enable
> the MMU+dcache instead?
>
OK. can do that.
>
>> +
>> + tbl[index] = (pgtbl_mem + PAGE_SIZE * next_tbl_cnt) | PMD_TYPE_TABLE;
>> +
>> + return &pgtbl_buf[(next_tbl_cnt++ * PAGE_SIZE) >> 3];
>> +}
>> +
>> +static void craete_block_entry(unsigned long *tbl, unsigned long flags,
>> + unsigned long phys, unsigned long virt)
>
> Why have separate phys and virt parameters if all this ever does is idmap?
Agreed.
>
>
>> +{
>> + unsigned long index;
>> + unsigned long desc;
>> +
>> + index = (virt >> PMD_SHIFT) & PTRS_PER_PMD;
>
> Copying the pmd_index() macro would make this clearer.
Right.
>
>
>> + desc = (phys >> PMD_SHIFT) << PMD_SHIFT;
>
> Looks like you wanted a PMD_MASK.
Right.
>
>
>> + desc |= flags;
>> + tbl[index] = desc;
>> +}
>> +
>> +static void create_identity_entry(unsigned long *pgtbl_buf,
>> + unsigned long pgtbl_mem, unsigned long virt,
>> + unsigned long flags)
>> +{
>> + unsigned long *tbl = pgtbl_buf;
>> +
>> + tbl = create_table_entry(pgtbl_buf, pgtbl_mem, tbl, virt,
>> + PGDIR_SHIFT, PTRS_PER_PGD);
>> + tbl = create_table_entry(pgtbl_buf, pgtbl_mem, tbl, virt,
>> + PUD_SHIFT, PTRS_PER_PUD);
>> + craete_block_entry(tbl, flags, virt, virt);
>
> Nit: create
Ok.
>
>> +}
>> +
>> +/**
>> + * arm64_create_pgtbl_segment - Create page table segments to be used by
>> + * purgatory. Page table will have entries to access memory area of all
>> + * those segments which becomes part of sha verification in purgatory.
>> + * Additionaly, we also create page table for purgatory segment as well.
>
> Nit: additionally,
Ok.
>
>> + */
>> +
>> +static int arm64_create_pgtbl_segment(struct kexec_info *info,
>> + unsigned long hole_min, unsigned long hole_max)
>> +{
>> + unsigned long *pgtbl_buf;
>> + int i;
>> + unsigned long mstart, mend, pgtbl_mem;
>> + unsigned long purgatory_base, purgatory_len;
>> +
>> + pgtbl_buf = xmalloc(MAX_PGTBLE_SZ);
>> + memset(pgtbl_buf, 0, MAX_PGTBLE_SZ);
>
>> + pgtbl_mem = add_buffer_phys_virt(info, pgtbl_buf, MAX_PGTBLE_SZ,
>> + MAX_PGTBLE_SZ, PAGE_SIZE, hole_min, hole_max, 1, 0);
>
> I want to check what this does, but this all looks like it is doing the right thing.
>
>
>> + for (i = 0; i < info->nr_segments; i++) {
>> + if (info->segment[i].mem == (void *)info->rhdr.rel_addr) {
>> + purgatory_base = (unsigned long)info->segment[i].mem;
>> + purgatory_len = info->segment[i].memsz;
>> + }
>> + mstart = (unsigned long)info->segment[i].mem;
>> + mend = mstart + info->segment[i].memsz;
>> + mstart &= ~(SECTION_SIZE - 1);
>> + while (mstart < mend) {
>> + create_identity_entry(pgtbl_buf, pgtbl_mem,
>> + mstart, MMU_FLAGS_NORMAL);
>> + mstart += SECTION_SIZE;
>> + }
>> + }
>
~Pratyush
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kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 22+ messages in thread
* [PATCH V2 0/2] kexec-tools: arm64: Enable D-cache in purgatory
2017-01-10 14:11 ` James Morse
@ 2017-02-23 5:59 ` Pratyush Anand
-1 siblings, 0 replies; 22+ messages in thread
From: Pratyush Anand @ 2017-02-23 5:59 UTC (permalink / raw)
To: linux-arm-kernel
Hi James and all,
Any review comment for patch 2/2?
If no, then I will address comment for 1/2 and will send v3.
~Pratyush
On Tuesday 10 January 2017 07:41 PM, James Morse wrote:
> Hi Pratyush,
>
> On 06/01/17 03:31, Pratyush Anand wrote:
>> Any feedback/review comment on it?
>
> I started going through this last week, I hope to get back to it later this
> week. (I also need to learn/remember how some of the kexec-tools stuff works).
>
>
> Thanks,
>
> James
>
>
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH V2 0/2] kexec-tools: arm64: Enable D-cache in purgatory
@ 2017-02-23 5:59 ` Pratyush Anand
0 siblings, 0 replies; 22+ messages in thread
From: Pratyush Anand @ 2017-02-23 5:59 UTC (permalink / raw)
To: James Morse; +Cc: geoff, mark.rutland, dyoung, kexec, linux-arm-kernel
Hi James and all,
Any review comment for patch 2/2?
If no, then I will address comment for 1/2 and will send v3.
~Pratyush
On Tuesday 10 January 2017 07:41 PM, James Morse wrote:
> Hi Pratyush,
>
> On 06/01/17 03:31, Pratyush Anand wrote:
>> Any feedback/review comment on it?
>
> I started going through this last week, I hope to get back to it later this
> week. (I also need to learn/remember how some of the kexec-tools stuff works).
>
>
> Thanks,
>
> James
>
>
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 22+ messages in thread
* [PATCH V2 1/2] kexec: arm64: create identity page table to be used in purgatory
2017-01-18 7:43 ` Pratyush Anand
@ 2017-03-15 9:42 ` Pratyush Anand
-1 siblings, 0 replies; 22+ messages in thread
From: Pratyush Anand @ 2017-03-15 9:42 UTC (permalink / raw)
To: linux-arm-kernel
Hi James,
On Wednesday 18 January 2017 01:13 PM, Pratyush Anand wrote:
>
>>
>>> + * in kexec
>>> + */
>>> + if (next_tbl_cnt > 5)
>>> + die("%s: No more memory for page table\n", __func__);
>>
>> die()? With a bit of juggling can't we return an error so we never try
>> to enable
>> the MMU+dcache instead?
>>
>
> OK. can do that.
It does not seem easy to do that. We will have to revert job of
add_buffer_phys_virt() in case of failure, and it will need lot of new
code. So, IMHO it would be better to keep die() as of now.
What do you say?
~Pratyush
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH V2 1/2] kexec: arm64: create identity page table to be used in purgatory
@ 2017-03-15 9:42 ` Pratyush Anand
0 siblings, 0 replies; 22+ messages in thread
From: Pratyush Anand @ 2017-03-15 9:42 UTC (permalink / raw)
To: James Morse; +Cc: geoff, mark.rutland, dyoung, kexec, linux-arm-kernel
Hi James,
On Wednesday 18 January 2017 01:13 PM, Pratyush Anand wrote:
>
>>
>>> + * in kexec
>>> + */
>>> + if (next_tbl_cnt > 5)
>>> + die("%s: No more memory for page table\n", __func__);
>>
>> die()? With a bit of juggling can't we return an error so we never try
>> to enable
>> the MMU+dcache instead?
>>
>
> OK. can do that.
It does not seem easy to do that. We will have to revert job of
add_buffer_phys_virt() in case of failure, and it will need lot of new
code. So, IMHO it would be better to keep die() as of now.
What do you say?
~Pratyush
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 22+ messages in thread
end of thread, other threads:[~2017-03-15 9:42 UTC | newest]
Thread overview: 22+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-12-19 7:13 [PATCH V2 0/2] kexec-tools: arm64: Enable D-cache in purgatory Pratyush Anand
2016-12-19 7:13 ` Pratyush Anand
2016-12-19 7:13 ` [PATCH V2 1/2] kexec: arm64: create identity page table to be used " Pratyush Anand
2016-12-19 7:13 ` Pratyush Anand
2016-12-19 7:21 ` Maxim Uvarov
2016-12-19 7:21 ` Maxim Uvarov
2016-12-19 7:23 ` Pratyush Anand
2016-12-19 7:23 ` Pratyush Anand
2017-01-17 17:25 ` James Morse
2017-01-17 17:25 ` James Morse
2017-01-18 7:43 ` Pratyush Anand
2017-01-18 7:43 ` Pratyush Anand
2017-03-15 9:42 ` Pratyush Anand
2017-03-15 9:42 ` Pratyush Anand
2016-12-19 7:13 ` [PATCH V2 2/2] arm64: enable d-cache support during purgatory sha verification Pratyush Anand
2016-12-19 7:13 ` Pratyush Anand
2017-01-06 3:31 ` [PATCH V2 0/2] kexec-tools: arm64: Enable D-cache in purgatory Pratyush Anand
2017-01-06 3:31 ` Pratyush Anand
2017-01-10 14:11 ` James Morse
2017-01-10 14:11 ` James Morse
2017-02-23 5:59 ` Pratyush Anand
2017-02-23 5:59 ` Pratyush Anand
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