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s390/bpf: Add kCFI support

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This is the s390 variant of commit 710618c760 ("arm64/cfi,bpf: Support
kCFI + BPF on arm64").

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Ilya Leoshkevich <iii@linux.ibm.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
Heiko Carstens
2026-07-27 16:05:12 +02:00
committed by Vasily Gorbik
parent 4133c9d3f3
commit 227b4e108a
2 changed files with 31 additions and 4 deletions
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7
arch/s390/include/asm/cfi.h Normal file
View File

@@ -0,0 +1,7 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_S390_CFI_H
#define _ASM_S390_CFI_H
#define __bpfcall
#endif /* _ASM_S390_CFI_H */

28
arch/s390/net/bpf_jit_comp.c
View File

@@ -21,6 +21,7 @@
#include <linux/filter.h>
#include <linux/init.h>
#include <linux/bpf.h>
#include <linux/cfi.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <asm/cacheflush.h>
@@ -356,6 +357,19 @@ static void emit6_pcrel_rilc(struct bpf_jit *jit, u32 op, u8 mask, s64 pcrel)
} \
})
static inline void emit_u32_data(const u32 data, struct bpf_jit *jit)
{
if (jit->prg_buf)
*(u32 *)(jit->prg_buf + jit->prg) = data;
jit->prg += 4;
}
static inline void emit_kcfi(u32 hash, struct bpf_jit *jit)
{
if (IS_ENABLED(CONFIG_CFI))
emit_u32_data(hash, jit);
}
/*
* Return whether this is the first pass. The first pass is special, since we
* don't know any sizes yet, and thus must be conservative.
@@ -597,6 +611,8 @@ static void bpf_jit_prologue(struct bpf_jit *jit, struct bpf_prog *fp)
{
BUILD_BUG_ON(sizeof(struct prog_frame) != STACK_FRAME_OVERHEAD);
emit_kcfi(bpf_is_subprog(fp) ? cfi_bpf_subprog_hash : cfi_bpf_hash, jit);
/* No-op for hotpatching */
/* brcl 0,prologue_plt */
EMIT6_PCREL_RILC(0xc0040000, 0, jit->prologue_plt);
@@ -616,7 +632,7 @@ static void bpf_jit_prologue(struct bpf_jit *jit, struct bpf_prog *fp)
bpf_skip(jit, 6);
}
/* Tail calls have to skip above initialization */
jit->tail_call_start = jit->prg;
jit->tail_call_start = jit->prg - cfi_get_offset();
if (fp->aux->exception_cb) {
/*
* Switch stack, the new address is in the 2nd parameter.
@@ -2401,11 +2417,13 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_verifier_env *env, struct bpf_pr
jit_data->ctx = jit;
jit_data->pass = pass;
}
fp->bpf_func = (void *) jit.prg_buf;
fp->bpf_func = (void *)jit.prg_buf + cfi_get_offset();
fp->jited = 1;
fp->jited_len = jit.size;
fp->jited_len = jit.size - cfi_get_offset();
if (!fp->is_func || extra_pass) {
for (int i = 0; i < fp->len; i++)
jit.addrs[i] -= cfi_get_offset();
bpf_prog_fill_jited_linfo(fp, jit.addrs + 1);
free_addrs:
kvfree(jit.addrs);
@@ -2671,8 +2689,10 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im,
return -ENOTSUPP;
/* Return to %r14 in the struct_ops case. */
if (flags & BPF_TRAMP_F_INDIRECT)
if (flags & BPF_TRAMP_F_INDIRECT) {
flags |= BPF_TRAMP_F_SKIP_FRAME;
emit_kcfi(cfi_get_func_hash(func_addr), jit);
}
/*
* Compute how many arguments we need to pass to BPF programs.