[PATCH 2/2] RISC-V: Support MODULE_SECTIONS mechanism on RV32

From: Zong Li
Date: Sun Nov 11 2018 - 23:10:01 EST


This patch supports dynamic generate got and plt sections mechanism on
rv32. It contains the modification as follows:
- Always enable MODULE_SECTIONS (both rv64 and rv32)
- Change the fixed size type.

This patch had been tested by following modules:

btrfs 6795991 0 - Live 0xa544b000
test_static_keys 17304 0 - Live 0xa28be000
zstd_compress 1198986 1 btrfs, Live 0xa2a25000
zstd_decompress 608112 1 btrfs, Live 0xa24e7000
lzo 8787 0 - Live 0xa2049000
xor 27461 1 btrfs, Live 0xa2041000
zram 78849 0 - Live 0xa2276000
netdevsim 55909 0 - Live 0xa202d000
tun 211534 0 - Live 0xa21b5000
fuse 566049 0 - Live 0xa25fb000
nfs_layout_flexfiles 192597 0 - Live 0xa229b000
ramoops 74895 0 - Live 0xa2019000
xfs 3973221 0 - Live 0xa507f000
libcrc32c 3053 2 btrfs,xfs, Live 0xa34af000
lzo_compress 17302 2 btrfs,lzo, Live 0xa347d000
lzo_decompress 7178 2 btrfs,lzo, Live 0xa3451000
raid6_pq 142086 1 btrfs, Live 0xa33a4000
reed_solomon 31022 1 ramoops, Live 0xa31eb000
test_bitmap 3734 0 - Live 0xa31af000
test_bpf 1588736 0 - Live 0xa2c11000
test_kmod 41161 0 - Live 0xa29f8000
test_module 1356 0 - Live 0xa299e000
test_printf 6024 0 [permanent], Live 0xa2971000
test_static_key_base 5797 1 test_static_keys, Live 0xa2931000
test_user_copy 4382 0 - Live 0xa28c9000
xxhash 70501 2 zstd_compress,zstd_decompress, Live 0xa2055000

Signed-off-by: Zong Li <zong@xxxxxxxxxxxxx>
---
arch/riscv/Kconfig | 2 +-
arch/riscv/include/asm/module.h | 28 +++++++++++++++-------------
arch/riscv/kernel/module-sections.c | 30 ++++++++++++++++--------------
3 files changed, 32 insertions(+), 28 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 55da93f..477f1e8 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -39,6 +39,7 @@ config RISCV
select SYSCTL_EXCEPTION_TRACE
select HAVE_ARCH_TRACEHOOK
select MODULES_USE_ELF_RELA if MODULES
+ select MODULE_SECTIONS if MODULES
select THREAD_INFO_IN_TASK
select RISCV_TIMER
select GENERIC_IRQ_MULTI_HANDLER
@@ -149,7 +150,6 @@ choice
bool "2GiB"
config MAXPHYSMEM_128GB
depends on 64BIT && CMODEL_MEDANY
- select MODULE_SECTIONS if MODULES
bool "128GiB"
endchoice

diff --git a/arch/riscv/include/asm/module.h b/arch/riscv/include/asm/module.h
index 349df33..27328fe 100644
--- a/arch/riscv/include/asm/module.h
+++ b/arch/riscv/include/asm/module.h
@@ -8,12 +8,12 @@

#define MODULE_ARCH_VERMAGIC "riscv"

-u64 module_emit_got_entry(struct module *mod, u64 val);
-u64 module_emit_plt_entry(struct module *mod, u64 val);
+unsigned long module_emit_got_entry(struct module *mod, unsigned long val);
+unsigned long module_emit_plt_entry(struct module *mod, unsigned long val);

#ifdef CONFIG_MODULE_SECTIONS
struct mod_section {
- struct elf64_shdr *shdr;
+ Elf_Shdr *shdr;
int num_entries;
int max_entries;
};
@@ -25,18 +25,18 @@ struct mod_arch_specific {
};

struct got_entry {
- u64 symbol_addr; /* the real variable address */
+ unsigned long symbol_addr; /* the real variable address */
};

-static inline struct got_entry emit_got_entry(u64 val)
+static inline struct got_entry emit_got_entry(unsigned long val)
{
return (struct got_entry) {val};
}

-static inline struct got_entry *get_got_entry(u64 val,
+static inline struct got_entry *get_got_entry(unsigned long val,
const struct mod_section *sec)
{
- struct got_entry *got = (struct got_entry *)sec->shdr->sh_addr;
+ struct got_entry *got = (struct got_entry *)(sec->shdr->sh_addr);
int i;
for (i = 0; i < sec->num_entries; i++) {
if (got[i].symbol_addr == val)
@@ -61,7 +61,9 @@ struct plt_entry {
#define REG_T0 0x5
#define REG_T1 0x6

-static inline struct plt_entry emit_plt_entry(u64 val, u64 plt, u64 got_plt)
+static inline struct plt_entry emit_plt_entry(unsigned long val,
+ unsigned long plt,
+ unsigned long got_plt)
{
/*
* U-Type encoding:
@@ -75,7 +77,7 @@ static inline struct plt_entry emit_plt_entry(u64 val, u64 plt, u64 got_plt)
* +------------+------------+--------+----------+----------+
*
*/
- u64 offset = got_plt - plt;
+ unsigned long offset = got_plt - plt;
u32 hi20 = (offset + 0x800) & 0xfffff000;
u32 lo12 = (offset - hi20);
return (struct plt_entry) {
@@ -85,7 +87,7 @@ static inline struct plt_entry emit_plt_entry(u64 val, u64 plt, u64 got_plt)
};
}

-static inline int get_got_plt_idx(u64 val, const struct mod_section *sec)
+static inline int get_got_plt_idx(unsigned long val, const struct mod_section *sec)
{
struct got_entry *got_plt = (struct got_entry *)sec->shdr->sh_addr;
int i;
@@ -96,9 +98,9 @@ static inline int get_got_plt_idx(u64 val, const struct mod_section *sec)
return -1;
}

-static inline struct plt_entry *get_plt_entry(u64 val,
- const struct mod_section *sec_plt,
- const struct mod_section *sec_got_plt)
+static inline struct plt_entry *get_plt_entry(unsigned long val,
+ const struct mod_section *sec_plt,
+ const struct mod_section *sec_got_plt)
{
struct plt_entry *plt = (struct plt_entry *)sec_plt->shdr->sh_addr;
int got_plt_idx = get_got_plt_idx(val, sec_got_plt);
diff --git a/arch/riscv/kernel/module-sections.c b/arch/riscv/kernel/module-sections.c
index bbbd26e..e8b991a 100644
--- a/arch/riscv/kernel/module-sections.c
+++ b/arch/riscv/kernel/module-sections.c
@@ -9,14 +9,14 @@
#include <linux/kernel.h>
#include <linux/module.h>

-u64 module_emit_got_entry(struct module *mod, u64 val)
+unsigned long module_emit_got_entry(struct module *mod, unsigned long val)
{
struct mod_section *got_sec = &mod->arch.got;
int i = got_sec->num_entries;
struct got_entry *got = get_got_entry(val, got_sec);

if (got)
- return (u64)got;
+ return (unsigned long)got;

/* There is no duplicate entry, create a new one */
got = (struct got_entry *)got_sec->shdr->sh_addr;
@@ -25,10 +25,10 @@ u64 module_emit_got_entry(struct module *mod, u64 val)
got_sec->num_entries++;
BUG_ON(got_sec->num_entries > got_sec->max_entries);

- return (u64)&got[i];
+ return (unsigned long)&got[i];
}

-u64 module_emit_plt_entry(struct module *mod, u64 val)
+unsigned long module_emit_plt_entry(struct module *mod, unsigned long val)
{
struct mod_section *got_plt_sec = &mod->arch.got_plt;
struct got_entry *got_plt;
@@ -37,27 +37,29 @@ u64 module_emit_plt_entry(struct module *mod, u64 val)
int i = plt_sec->num_entries;

if (plt)
- return (u64)plt;
+ return (unsigned long)plt;

/* There is no duplicate entry, create a new one */
got_plt = (struct got_entry *)got_plt_sec->shdr->sh_addr;
got_plt[i] = emit_got_entry(val);
plt = (struct plt_entry *)plt_sec->shdr->sh_addr;
- plt[i] = emit_plt_entry(val, (u64)&plt[i], (u64)&got_plt[i]);
+ plt[i] = emit_plt_entry(val,
+ (unsigned long)&plt[i],
+ (unsigned long)&got_plt[i]);

plt_sec->num_entries++;
got_plt_sec->num_entries++;
BUG_ON(plt_sec->num_entries > plt_sec->max_entries);

- return (u64)&plt[i];
+ return (unsigned long)&plt[i];
}

-static int is_rela_equal(const Elf64_Rela *x, const Elf64_Rela *y)
+static int is_rela_equal(const Elf_Rela *x, const Elf_Rela *y)
{
return x->r_info == y->r_info && x->r_addend == y->r_addend;
}

-static bool duplicate_rela(const Elf64_Rela *rela, int idx)
+static bool duplicate_rela(const Elf_Rela *rela, int idx)
{
int i;
for (i = 0; i < idx; i++) {
@@ -67,13 +69,13 @@ static bool duplicate_rela(const Elf64_Rela *rela, int idx)
return false;
}

-static void count_max_entries(Elf64_Rela *relas, int num,
+static void count_max_entries(Elf_Rela *relas, int num,
unsigned int *plts, unsigned int *gots)
{
unsigned int type, i;

for (i = 0; i < num; i++) {
- type = ELF64_R_TYPE(relas[i].r_info);
+ type = ELF_RISCV_R_TYPE(relas[i].r_info);
if (type == R_RISCV_CALL_PLT) {
if (!duplicate_rela(relas, i))
(*plts)++;
@@ -118,9 +120,9 @@ int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,

/* Calculate the maxinum number of entries */
for (i = 0; i < ehdr->e_shnum; i++) {
- Elf64_Rela *relas = (void *)ehdr + sechdrs[i].sh_offset;
- int num_rela = sechdrs[i].sh_size / sizeof(Elf64_Rela);
- Elf64_Shdr *dst_sec = sechdrs + sechdrs[i].sh_info;
+ Elf_Rela *relas = (void *)ehdr + sechdrs[i].sh_offset;
+ int num_rela = sechdrs[i].sh_size / sizeof(Elf_Rela);
+ Elf_Shdr *dst_sec = sechdrs + sechdrs[i].sh_info;

if (sechdrs[i].sh_type != SHT_RELA)
continue;
--
2.7.4