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LoongArch: vDSO: Wire up getrandom() vDSO implementation

Hook up the generic vDSO implementation to the LoongArch vDSO data page
by providing the required __arch_chacha20_blocks_nostack,
__arch_get_k_vdso_rng_data, and getrandom_syscall implementations. Also
wire up the selftests.

Signed-off-by: Xi Ruoyao <xry111@xry111.site>
Acked-by: Huacai Chen <chenhuacai@kernel.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Xi Ruoyao 2024-09-01 14:13:11 +08:00 committed by Jason A. Donenfeld
parent 4d456f0c87
commit 18efd0b10e
11 changed files with 316 additions and 2 deletions

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@ -190,6 +190,7 @@ config LOONGARCH
select TRACE_IRQFLAGS_SUPPORT
select USE_PERCPU_NUMA_NODE_ID
select USER_STACKTRACE_SUPPORT
select VDSO_GETRANDOM
select ZONE_DMA32
config 32BIT

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@ -0,0 +1,39 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2024 Xi Ruoyao <xry111@xry111.site>. All Rights Reserved.
*/
#ifndef __ASM_VDSO_GETRANDOM_H
#define __ASM_VDSO_GETRANDOM_H
#ifndef __ASSEMBLY__
#include <asm/unistd.h>
#include <asm/vdso/vdso.h>
static __always_inline ssize_t getrandom_syscall(void *_buffer, size_t _len, unsigned int _flags)
{
register long ret asm("a0");
register long nr asm("a7") = __NR_getrandom;
register void *buffer asm("a0") = _buffer;
register size_t len asm("a1") = _len;
register unsigned int flags asm("a2") = _flags;
asm volatile(
" syscall 0\n"
: "+r" (ret)
: "r" (nr), "r" (buffer), "r" (len), "r" (flags)
: "$t0", "$t1", "$t2", "$t3", "$t4", "$t5", "$t6", "$t7", "$t8",
"memory");
return ret;
}
static __always_inline const struct vdso_rng_data *__arch_get_vdso_rng_data(void)
{
return (const struct vdso_rng_data *)(get_vdso_data() + VVAR_LOONGARCH_PAGES_START *
PAGE_SIZE + offsetof(struct loongarch_vdso_data, rng_data));
}
#endif /* !__ASSEMBLY__ */
#endif /* __ASM_VDSO_GETRANDOM_H */

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@ -4,6 +4,9 @@
* Copyright (C) 2020-2022 Loongson Technology Corporation Limited
*/
#ifndef _ASM_VDSO_VDSO_H
#define _ASM_VDSO_VDSO_H
#ifndef __ASSEMBLY__
#include <asm/asm.h>
@ -16,6 +19,7 @@ struct vdso_pcpu_data {
struct loongarch_vdso_data {
struct vdso_pcpu_data pdata[NR_CPUS];
struct vdso_rng_data rng_data;
};
/*
@ -63,3 +67,5 @@ static inline unsigned long get_vdso_data(void)
}
#endif /* __ASSEMBLY__ */
#endif

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@ -8,6 +8,7 @@
#include <vdso/datapage.h>
extern struct vdso_data *vdso_data;
extern struct vdso_rng_data *vdso_rng_data;
/*
* Update the vDSO data page to keep in sync with kernel timekeeping.
@ -19,6 +20,13 @@ struct vdso_data *__loongarch_get_k_vdso_data(void)
}
#define __arch_get_k_vdso_data __loongarch_get_k_vdso_data
static __always_inline
struct vdso_rng_data *__loongarch_get_k_vdso_rng_data(void)
{
return vdso_rng_data;
}
#define __arch_get_k_vdso_rng_data __loongarch_get_k_vdso_rng_data
/* The asm-generic header needs to be included after the definitions above */
#include <asm-generic/vdso/vsyscall.h>

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@ -37,6 +37,7 @@ static union {
static struct page *vdso_pages[] = { NULL };
struct vdso_data *vdso_data = generic_vdso_data.data;
struct vdso_pcpu_data *vdso_pdata = loongarch_vdso_data.vdata.pdata;
struct vdso_rng_data *vdso_rng_data = &loongarch_vdso_data.vdata.rng_data;
static int vdso_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma)
{

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@ -4,7 +4,8 @@
# Include the generic Makefile to check the built vdso.
include $(srctree)/lib/vdso/Makefile
obj-vdso-y := elf.o vgetcpu.o vgettimeofday.o sigreturn.o
obj-vdso-y := elf.o vgetcpu.o vgettimeofday.o vgetrandom.o \
vgetrandom-chacha.o sigreturn.o
# Common compiler flags between ABIs.
ccflags-vdso := \
@ -29,6 +30,10 @@ ifneq ($(c-gettimeofday-y),)
CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y)
endif
ifneq ($(c-getrandom-y),)
CFLAGS_vgetrandom.o += -include $(c-getrandom-y)
endif
# VDSO linker flags.
ldflags-y := -Bsymbolic --no-undefined -soname=linux-vdso.so.1 \
$(filter -E%,$(KBUILD_CFLAGS)) -nostdlib -shared \

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@ -62,6 +62,7 @@ VERSION
__vdso_clock_getres;
__vdso_clock_gettime;
__vdso_gettimeofday;
__vdso_getrandom;
__vdso_rt_sigreturn;
local: *;
};

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@ -0,0 +1,242 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2024 Xi Ruoyao <xry111@xry111.site>. All Rights Reserved.
*/
#include <asm/asm.h>
#include <asm/regdef.h>
#include <linux/linkage.h>
.text
/* Salsa20 quarter-round */
.macro QR a b c d
add.w \a, \a, \b
xor \d, \d, \a
rotri.w \d, \d, 16
add.w \c, \c, \d
xor \b, \b, \c
rotri.w \b, \b, 20
add.w \a, \a, \b
xor \d, \d, \a
rotri.w \d, \d, 24
add.w \c, \c, \d
xor \b, \b, \c
rotri.w \b, \b, 25
.endm
/*
* Very basic LoongArch implementation of ChaCha20. Produces a given positive
* number of blocks of output with a nonce of 0, taking an input key and
* 8-byte counter. Importantly does not spill to the stack. Its arguments
* are:
*
* a0: output bytes
* a1: 32-byte key input
* a2: 8-byte counter input/output
* a3: number of 64-byte blocks to write to output
*/
SYM_FUNC_START(__arch_chacha20_blocks_nostack)
/* We don't need a frame pointer */
#define s9 fp
#define output a0
#define key a1
#define counter a2
#define nblocks a3
#define i a4
#define state0 s0
#define state1 s1
#define state2 s2
#define state3 s3
#define state4 s4
#define state5 s5
#define state6 s6
#define state7 s7
#define state8 s8
#define state9 s9
#define state10 a5
#define state11 a6
#define state12 a7
#define state13 t0
#define state14 t1
#define state15 t2
#define cnt_lo t3
#define cnt_hi t4
#define copy0 t5
#define copy1 t6
#define copy2 t7
/* Reuse i as copy3 */
#define copy3 i
/*
* The ABI requires s0-s9 saved, and sp aligned to 16-byte.
* This does not violate the stack-less requirement: no sensitive data
* is spilled onto the stack.
*/
PTR_ADDI sp, sp, (-SZREG * 10) & STACK_ALIGN
REG_S s0, sp, 0
REG_S s1, sp, SZREG
REG_S s2, sp, SZREG * 2
REG_S s3, sp, SZREG * 3
REG_S s4, sp, SZREG * 4
REG_S s5, sp, SZREG * 5
REG_S s6, sp, SZREG * 6
REG_S s7, sp, SZREG * 7
REG_S s8, sp, SZREG * 8
REG_S s9, sp, SZREG * 9
li.w copy0, 0x61707865
li.w copy1, 0x3320646e
li.w copy2, 0x79622d32
ld.w cnt_lo, counter, 0
ld.w cnt_hi, counter, 4
.Lblock:
/* state[0,1,2,3] = "expand 32-byte k" */
move state0, copy0
move state1, copy1
move state2, copy2
li.w state3, 0x6b206574
/* state[4,5,..,11] = key */
ld.w state4, key, 0
ld.w state5, key, 4
ld.w state6, key, 8
ld.w state7, key, 12
ld.w state8, key, 16
ld.w state9, key, 20
ld.w state10, key, 24
ld.w state11, key, 28
/* state[12,13] = counter */
move state12, cnt_lo
move state13, cnt_hi
/* state[14,15] = 0 */
move state14, zero
move state15, zero
li.w i, 10
.Lpermute:
/* odd round */
QR state0, state4, state8, state12
QR state1, state5, state9, state13
QR state2, state6, state10, state14
QR state3, state7, state11, state15
/* even round */
QR state0, state5, state10, state15
QR state1, state6, state11, state12
QR state2, state7, state8, state13
QR state3, state4, state9, state14
addi.w i, i, -1
bnez i, .Lpermute
/*
* copy[3] = "expa", materialize it here because copy[3] shares the
* same register with i which just became dead.
*/
li.w copy3, 0x6b206574
/* output[0,1,2,3] = copy[0,1,2,3] + state[0,1,2,3] */
add.w state0, state0, copy0
add.w state1, state1, copy1
add.w state2, state2, copy2
add.w state3, state3, copy3
st.w state0, output, 0
st.w state1, output, 4
st.w state2, output, 8
st.w state3, output, 12
/* from now on state[0,1,2,3] are scratch registers */
/* state[0,1,2,3] = lo32(key) */
ld.w state0, key, 0
ld.w state1, key, 4
ld.w state2, key, 8
ld.w state3, key, 12
/* output[4,5,6,7] = state[0,1,2,3] + state[4,5,6,7] */
add.w state4, state4, state0
add.w state5, state5, state1
add.w state6, state6, state2
add.w state7, state7, state3
st.w state4, output, 16
st.w state5, output, 20
st.w state6, output, 24
st.w state7, output, 28
/* state[0,1,2,3] = hi32(key) */
ld.w state0, key, 16
ld.w state1, key, 20
ld.w state2, key, 24
ld.w state3, key, 28
/* output[8,9,10,11] = state[0,1,2,3] + state[8,9,10,11] */
add.w state8, state8, state0
add.w state9, state9, state1
add.w state10, state10, state2
add.w state11, state11, state3
st.w state8, output, 32
st.w state9, output, 36
st.w state10, output, 40
st.w state11, output, 44
/* output[12,13,14,15] = state[12,13,14,15] + [cnt_lo, cnt_hi, 0, 0] */
add.w state12, state12, cnt_lo
add.w state13, state13, cnt_hi
st.w state12, output, 48
st.w state13, output, 52
st.w state14, output, 56
st.w state15, output, 60
/* ++counter */
addi.w cnt_lo, cnt_lo, 1
sltui state0, cnt_lo, 1
add.w cnt_hi, cnt_hi, state0
/* output += 64 */
PTR_ADDI output, output, 64
/* --nblocks */
PTR_ADDI nblocks, nblocks, -1
bnez nblocks, .Lblock
/* counter = [cnt_lo, cnt_hi] */
st.w cnt_lo, counter, 0
st.w cnt_hi, counter, 4
/*
* Zero out the potentially sensitive regs, in case nothing uses these
* again. As at now copy[0,1,2,3] just contains "expand 32-byte k" and
* state[0,...,9] are s0-s9 those we'll restore in the epilogue, so we
* only need to zero state[11,...,15].
*/
move state10, zero
move state11, zero
move state12, zero
move state13, zero
move state14, zero
move state15, zero
REG_L s0, sp, 0
REG_L s1, sp, SZREG
REG_L s2, sp, SZREG * 2
REG_L s3, sp, SZREG * 3
REG_L s4, sp, SZREG * 4
REG_L s5, sp, SZREG * 5
REG_L s6, sp, SZREG * 6
REG_L s7, sp, SZREG * 7
REG_L s8, sp, SZREG * 8
REG_L s9, sp, SZREG * 9
PTR_ADDI sp, sp, -((-SZREG * 10) & STACK_ALIGN)
jr ra
SYM_FUNC_END(__arch_chacha20_blocks_nostack)

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@ -0,0 +1,10 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2024 Xi Ruoyao <xry111@xry111.site>. All Rights Reserved.
*/
#include <linux/types.h>
ssize_t __vdso_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state, size_t opaque_len)
{
return __cvdso_getrandom(buffer, len, flags, opaque_state, opaque_len);
}

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tools/arch/loongarch/vdso Symbolic link
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@ -0,0 +1 @@
../../../arch/loongarch/vdso

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@ -9,7 +9,7 @@ ifeq ($(ARCH),$(filter $(ARCH),x86 x86_64))
TEST_GEN_PROGS += vdso_standalone_test_x86
endif
TEST_GEN_PROGS += vdso_test_correctness
ifeq ($(ARCH)$(CONFIG_X86_32),$(filter $(ARCH)$(CONFIG_X86_32),x86 x86_64))
ifeq ($(ARCH)$(CONFIG_X86_32),$(filter $(ARCH)$(CONFIG_X86_32),x86 x86_64 loongarch))
TEST_GEN_PROGS += vdso_test_getrandom
TEST_GEN_PROGS += vdso_test_chacha
endif