arm64: module: Fix PLT counting when CONFIG_RANDOMIZE_BASE=n

commit d35686444fc80950c731e33a2f6ad4a55822be9b upstream.

The counting of module PLTs has been broken when CONFIG_RANDOMIZE_BASE=n
since commit:

  3e35d303ab7d22c4 ("arm64: module: rework module VA range selection")

Prior to that commit, when CONFIG_RANDOMIZE_BASE=n, the kernel image and
all modules were placed within a 128M region, and no PLTs were necessary
for B or BL. Hence count_plts() and partition_branch_plt_relas() skipped
handling B and BL when CONFIG_RANDOMIZE_BASE=n.

After that commit, modules can be placed anywhere within a 2G window
regardless of CONFIG_RANDOMIZE_BASE, and hence PLTs may be necessary for
B and BL even when CONFIG_RANDOMIZE_BASE=n. Unfortunately that commit
failed to update count_plts() and partition_branch_plt_relas()
accordingly.

Due to this, module_emit_plt_entry() may fail if an insufficient number
of PLT entries have been reserved, resulting in modules failing to load
with -ENOEXEC.

Fix this by counting PLTs regardless of CONFIG_RANDOMIZE_BASE in
count_plts() and partition_branch_plt_relas().

Fixes: 3e35d303ab7d ("arm64: module: rework module VA range selection")
Signed-off-by: Maria Yu <quic_aiquny@quicinc.com>
Cc: <stable@vger.kernel.org> # 6.5.x
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Fixes: 3e35d303ab7d ("arm64: module: rework module VA range selection")
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20231024010954.6768-1-quic_aiquny@quicinc.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/arm64/kernel/module-plts.c b/arch/arm64/kernel/module-plts.c
index bd69a4e..79200f2 100644 (file)
--- a/arch/arm64/kernel/module-plts.c
+++ b/arch/arm64/kernel/module-plts.c
@@ -167,9 +167,6 @@ static unsigned int count_plts(Elf64_Sym *syms, Elf64_Rela *rela, int num,
                switch (ELF64_R_TYPE(rela[i].r_info)) {
                case R_AARCH64_JUMP26:
                case R_AARCH64_CALL26:
-                       if (!IS_ENABLED(CONFIG_RANDOMIZE_BASE))
-                               break;
-
                        /*
                         * We only have to consider branch targets that resolve
                         * to symbols that are defined in a different section.
@@ -269,9 +266,6 @@ static int partition_branch_plt_relas(Elf64_Sym *syms, Elf64_Rela *rela,
 {
        int i = 0, j = numrels - 1;
 
-       if (!IS_ENABLED(CONFIG_RANDOMIZE_BASE))
-               return 0;
-
        while (i < j) {
                if (branch_rela_needs_plt(syms, &rela[i], dstidx))
                        i++;