155 lines
5.5 KiB
Diff
155 lines
5.5 KiB
Diff
From 74474a366d1244d344ad9ff222e8e2351a96af8c Mon Sep 17 00:00:00 2001
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From: HATAYAMA Daisuke <d.hatayama@fujitsu.com>
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Date: Fri, 25 Dec 2020 15:48:50 +0900
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Subject: [PATCH 09/11] memory, zram: introduce and export readswap()
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try_zram_decompress() is currently exported to extension modules, but
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from a viewpoint of author of extension modules, it's better to export
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an interface to read memory on swap; difference of decompressor are
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then hidden within the interface and there is no need for extension
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modules to update accordingly each time new decompressor are added in
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the future.
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So let's introduce function readswap() as an interface to read memory
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on swap.
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Signed-off-by: HATAYAMA Daisuke <d.hatayama@fujitsu.com>
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---
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defs.h | 1 +
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diskdump.c | 63 ++++++++++++++++++++++++++++++++++++++----------------
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memory.c | 2 +-
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3 files changed, 46 insertions(+), 20 deletions(-)
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diff --git a/defs.h b/defs.h
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index ebd7bb615b61..c29b3fa3dee9 100644
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--- a/defs.h
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+++ b/defs.h
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@@ -6539,6 +6539,7 @@ int diskdump_get_nr_cpus(void);
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QEMUCPUState *diskdump_get_qemucpustate(int);
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void diskdump_device_dump_info(FILE *);
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void diskdump_device_dump_extract(int, char *, FILE *);
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+ulong readswap(ulonglong pte_val, char *buf, ulong len, ulonglong vaddr);
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/*support for zram*/
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ulong try_zram_decompress(ulonglong pte_val, unsigned char *buf, ulong len, ulonglong vaddr);
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#define OBJ_TAG_BITS 1
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diff --git a/diskdump.c b/diskdump.c
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index a4ca38f6c732..03a77a977646 100644
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--- a/diskdump.c
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+++ b/diskdump.c
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@@ -2709,24 +2709,13 @@ lookup_swap_cache(ulonglong pte_val, unsigned char *zram_buf)
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return NULL;
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}
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-ulong (*decompressor)(unsigned char *in_addr, ulong in_size, unsigned char *out_addr, ulong *out_size, void *other/* NOT USED */);
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-/*
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- * If userspace address was swapped out to zram, this function is called to decompress the object.
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- * try_zram_decompress returns decompressed page data and data length
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- */
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-ulong
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-try_zram_decompress(ulonglong pte_val, unsigned char *buf, ulong len, ulonglong vaddr)
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+static int get_disk_name_private_data(ulonglong pte_val, ulonglong vaddr,
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+ char *name, ulong *private_data)
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{
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- char name[32] = {0};
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- ulonglong swp_offset;
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- ulong swap_info, bdev, bd_disk, zram, zram_table_entry, sector, index, entry, flags, size, outsize, off;
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- unsigned char *obj_addr = NULL;
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- unsigned char *zram_buf = NULL;
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- unsigned char *outbuf = NULL;
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+ ulong swap_info, bdev, bd_disk;
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- off = PAGEOFFSET(vaddr);
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if (!symbol_exists("swap_info"))
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- return 0;
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+ return FALSE;
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swap_info = symbol_value("swap_info");
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@@ -2743,14 +2732,49 @@ try_zram_decompress(ulonglong pte_val, unsigned char *buf, ulong len, ulonglong
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sizeof(void *), "swap_info_struct_bdev", FAULT_ON_ERROR);
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readmem(bdev + OFFSET(block_device_bd_disk), KVADDR, &bd_disk,
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sizeof(void *), "block_device_bd_disk", FAULT_ON_ERROR);
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- readmem(bd_disk + OFFSET(gendisk_disk_name), KVADDR, name,
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+ if (name)
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+ readmem(bd_disk + OFFSET(gendisk_disk_name), KVADDR, name,
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strlen("zram"), "gendisk_disk_name", FAULT_ON_ERROR);
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+ if (private_data)
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+ readmem(bd_disk + OFFSET(gendisk_private_data), KVADDR,
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+ private_data, sizeof(void *), "gendisk_private_data",
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+ FAULT_ON_ERROR);
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+
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+ return TRUE;
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+}
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+
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+ulong readswap(ulonglong pte_val, char *buf, ulong len, ulonglong vaddr)
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+{
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+ char name[32] = {0};
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- if (strncmp(name, "zram", strlen("zram"))) {
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+ if (!get_disk_name_private_data(pte_val, vaddr, name, NULL))
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+ return 0;
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+
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+ if (!strncmp(name, "zram", 4)) {
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+ return try_zram_decompress(pte_val, (unsigned char *)buf, len, vaddr);
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+ } else {
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if (CRASHDEBUG(2))
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error(WARNING, "this page has been swapped to %s\n", name);
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return 0;
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}
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+}
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+
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+ulong (*decompressor)(unsigned char *in_addr, ulong in_size, unsigned char *out_addr,
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+ ulong *out_size, void *other/* NOT USED */);
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+/*
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+ * If userspace address was swapped out to zram, this function is called to decompress the object.
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+ * try_zram_decompress returns decompressed page data and data length
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+ */
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+ulong
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+try_zram_decompress(ulonglong pte_val, unsigned char *buf, ulong len, ulonglong vaddr)
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+{
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+ char name[32] = {0};
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+ ulonglong swp_offset;
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+ unsigned char *obj_addr = NULL;
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+ unsigned char *zram_buf = NULL;
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+ unsigned char *outbuf = NULL;
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+ ulong zram, zram_table_entry, sector, index, entry, flags, size,
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+ outsize, off;
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if (INVALID_MEMBER(zram_compressor)) {
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zram_init();
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@@ -2765,8 +2789,8 @@ try_zram_decompress(ulonglong pte_val, unsigned char *buf, ulong len, ulonglong
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if (CRASHDEBUG(2))
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error(WARNING, "this page has swapped to zram\n");
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- readmem(bd_disk + OFFSET(gendisk_private_data), KVADDR, &zram,
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- sizeof(void *), "gendisk_private_data", FAULT_ON_ERROR);
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+ if (!get_disk_name_private_data(pte_val, vaddr, NULL, &zram))
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+ return 0;
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readmem(zram + OFFSET(zram_compressor), KVADDR, name,
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sizeof(name), "zram compressor", FAULT_ON_ERROR);
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@@ -2798,6 +2822,7 @@ try_zram_decompress(ulonglong pte_val, unsigned char *buf, ulong len, ulonglong
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zram_buf = (unsigned char *)GETBUF(PAGESIZE());
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/* lookup page from swap cache */
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+ off = PAGEOFFSET(vaddr);
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obj_addr = lookup_swap_cache(pte_val, zram_buf);
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if (obj_addr != NULL) {
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memcpy(buf, obj_addr + off, len);
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diff --git a/memory.c b/memory.c
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index 33b0ca7af977..17ac40b3e0f9 100644
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--- a/memory.c
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+++ b/memory.c
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@@ -2294,7 +2294,7 @@ readmem(ulonglong addr, int memtype, void *buffer, long size,
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if (cnt > size)
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cnt = size;
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- cnt = try_zram_decompress(paddr, (unsigned char *)bufptr, cnt, addr);
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+ cnt = readswap(paddr, bufptr, cnt, addr);
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if (cnt) {
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bufptr += cnt;
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addr += cnt;
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--
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2.29.2
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