On 2020-11-19 16:25, David Brazdil wrote:
The arm64 kernel also supports packing of relocation data using the
RELR
format. Implement a parser of RELR data and fixup the relocations using
the same infra as RELA relocs.
Signed-off-by: David Brazdil <dbraz...@google.com>
---
arch/arm64/kvm/va_layout.c | 41 ++++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)
diff --git a/arch/arm64/kvm/va_layout.c b/arch/arm64/kvm/va_layout.c
index b80fab974896..7f45a98eacfd 100644
--- a/arch/arm64/kvm/va_layout.c
+++ b/arch/arm64/kvm/va_layout.c
@@ -145,6 +145,43 @@ static void __fixup_hyp_rela(void)
__fixup_hyp_rel(rel[i].r_offset);
}
+#ifdef CONFIG_RELR
+static void __fixup_hyp_relr(void)
+{
+ u64 *rel, *end;
+
+ rel = (u64*)(kimage_vaddr + __load_elf_u64(__relr_offset));
+ end = rel + (__load_elf_u64(__relr_size) / sizeof(*rel));
+
+ while (rel < end) {
+ unsigned n;
+ u64 addr = *(rel++);
+
+ /* Address must not have the LSB set. */
+ BUG_ON(addr & BIT(0));
+
+ /* Fix up the first address of the chain. */
+ __fixup_hyp_rel(addr);
+
+ /*
+ * Loop over bitmaps, i.e. as long as words' LSB is 1.
+ * Each bit (ordered from LSB to MSB) represents one word from
+ * the last full address (exclusive). If the corresponding bit
+ * is 1, there is a relative relocation on that word.
+ */
What is the endianness of this bitmap? Is it guaranteed to be in
CPU-endian format?
+ for (n = 0; rel < end && (*rel & BIT(0)); n++) {
+ unsigned i;
+ u64 bitmap = *(rel++);
nit: if you change this u64 for an unsigned long...
+
+ for (i = 1; i < 64; ++i) {
+ if ((bitmap & BIT(i)))
+ __fixup_hyp_rel(addr + 8 * (63 * n +
i));
+ }
... this can be written as:
i = 1;
for_each_set_bit_from(i, &bitmap, 64)
__fixup_hyp_rel(addr + 8 * (63 * n + i));
+ }
+ }
+}
+#endif
+
/*
* The kernel relocated pointers to kernel VA. Iterate over
relocations in
* the hypervisor ELF sections and convert them to hyp VA. This avoids
the
@@ -156,6 +193,10 @@ __init void kvm_fixup_hyp_relocations(void)
return;
__fixup_hyp_rela();
+
+#ifdef CONFIG_RELR
+ __fixup_hyp_relr();
+#endif
}
static u32 compute_instruction(int n, u32 rd, u32 rn)
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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