github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-05-24 07:03:03 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

s390/bpf: Add macros for calling external functions

Browse Source 
After the V!=R rework (commit c98d2ecae0 ("s390/mm: Uncouple physical
vs virtual address spaces")), kernel and BPF programs are allocated
within a 4G region, making it possible to use relative addressing to
directly use kernel functions from BPF code.

Add two new macros for calling kernel functions from BPF code:
EMIT6_PCREL_RILB_PTR() and EMIT6_PCREL_RILC_PTR(). Factor out parts
of the existing macros that are helpful for implementing the new ones.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/20250519223646.66382-3-iii@linux.ibm.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Ilya Leoshkevich 2025-05-19 23:30:05 +01:00 committed by Alexei Starovoitov
parent f7562001c8
commit 9053ba042f
1 changed files with 43 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

62
arch/s390/net/bpf_jit_comp.c
View File

@ -127,6 +127,18 @@ static inline void reg_set_seen(struct bpf_jit *jit, u32 b1)
jit->seen_regs |= (1 << r1);
}
static s32 off_to_pcrel(struct bpf_jit *jit, u32 off)
{
return off - jit->prg;
}
static s64 ptr_to_pcrel(struct bpf_jit *jit, const void *ptr)
{
if (jit->prg_buf)
return (const u8 *)ptr - ((const u8 *)jit->prg_buf + jit->prg);
return 0;
}
#define REG_SET_SEEN(b1) \
({ \
reg_set_seen(jit, b1); \
@ -201,7 +213,7 @@ static inline void reg_set_seen(struct bpf_jit *jit, u32 b1)
#define EMIT4_PCREL_RIC(op, mask, target) \
({ \
int __rel = ((target) - jit->prg) / 2; \
int __rel = off_to_pcrel(jit, target) / 2; \
_EMIT4((op) | (mask) << 20 | (__rel & 0xffff)); \
})
@ -239,7 +251,7 @@ static inline void reg_set_seen(struct bpf_jit *jit, u32 b1)
#define EMIT6_PCREL_RIEB(op1, op2, b1, b2, mask, target) \
({ \
unsigned int rel = (int)((target) - jit->prg) / 2; \
unsigned int rel = off_to_pcrel(jit, target) / 2; \
_EMIT6((op1) | reg(b1, b2) << 16 | (rel & 0xffff), \
(op2) | (mask) << 12); \
REG_SET_SEEN(b1); \
@ -248,7 +260,7 @@ static inline void reg_set_seen(struct bpf_jit *jit, u32 b1)
#define EMIT6_PCREL_RIEC(op1, op2, b1, imm, mask, target) \
({ \
unsigned int rel = (int)((target) - jit->prg) / 2; \
unsigned int rel = off_to_pcrel(jit, target) / 2; \
_EMIT6((op1) | (reg_high(b1) | (mask)) << 16 | \
(rel & 0xffff), (op2) | ((imm) & 0xff) << 8); \
REG_SET_SEEN(b1); \
@ -257,29 +269,41 @@ static inline void reg_set_seen(struct bpf_jit *jit, u32 b1)
#define EMIT6_PCREL(op1, op2, b1, b2, i, off, mask) \
({ \
int rel = (addrs[(i) + (off) + 1] - jit->prg) / 2; \
int rel = off_to_pcrel(jit, addrs[(i) + (off) + 1]) / 2;\
_EMIT6((op1) | reg(b1, b2) << 16 | (rel & 0xffff), (op2) | (mask));\
REG_SET_SEEN(b1); \
REG_SET_SEEN(b2); \
})
#define EMIT6_PCREL_RILB(op, b, target) \
({ \
unsigned int rel = (int)((target) - jit->prg) / 2; \
_EMIT6((op) | reg_high(b) << 16 | rel >> 16, rel & 0xffff);\
REG_SET_SEEN(b); \
})
static void emit6_pcrel_ril(struct bpf_jit *jit, u32 op, s64 pcrel)
{
u32 pc32dbl = (s32)(pcrel / 2);
#define EMIT6_PCREL_RIL(op, target) \
({ \
unsigned int rel = (int)((target) - jit->prg) / 2; \
_EMIT6((op) | rel >> 16, rel & 0xffff); \
})
_EMIT6(op | pc32dbl >> 16, pc32dbl & 0xffff);
}
static void emit6_pcrel_rilb(struct bpf_jit *jit, u32 op, u8 b, s64 pcrel)
{
emit6_pcrel_ril(jit, op | reg_high(b) << 16, pcrel);
REG_SET_SEEN(b);
}
#define EMIT6_PCREL_RILB(op, b, target) \
emit6_pcrel_rilb(jit, op, b, off_to_pcrel(jit, target))
#define EMIT6_PCREL_RILB_PTR(op, b, target_ptr) \
emit6_pcrel_rilb(jit, op, b, ptr_to_pcrel(jit, target_ptr))
static void emit6_pcrel_rilc(struct bpf_jit *jit, u32 op, u8 mask, s64 pcrel)
{
emit6_pcrel_ril(jit, op | mask << 20, pcrel);
}
#define EMIT6_PCREL_RILC(op, mask, target) \
({ \
EMIT6_PCREL_RIL((op) | (mask) << 20, (target)); \
})
emit6_pcrel_rilc(jit, op, mask, off_to_pcrel(jit, target))
#define EMIT6_PCREL_RILC_PTR(op, mask, target_ptr) \
emit6_pcrel_rilc(jit, op, mask, ptr_to_pcrel(jit, target_ptr))
#define _EMIT6_IMM(op, imm) \
({ \
@ -503,7 +527,7 @@ static void bpf_skip(struct bpf_jit *jit, int size)
{
if (size >= 6 && !is_valid_rel(size)) {
/* brcl 0xf,size */
EMIT6_PCREL_RIL(0xc0f4000000, size);
EMIT6_PCREL_RILC(0xc0040000, 0xf, size);
size -= 6;
} else if (size >= 4 && is_valid_rel(size)) {
/* brc 0xf,size */