[PATCH v5 18/24] riscv: vdso: Enable the vdsocheck tool

["Thomas Weißschuh" <thomas.weissschuh@linutronix.de>]

The vdsocheck tool validates the object files and final .so library.
It can detect if the compiler created relocations which are incompatible
with the vDSO which need to be worked around.

Wire it up for the architecture.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
---
 arch/riscv/Kconfig              |  1 +
 arch/riscv/kernel/vdso/Makefile |  4 ++--
 lib/vdso/check/vdsocheck.rs     | 26 ++++++++++++++++++++++++++
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index f8e26c4bed2b..f580d2afecf7 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -229,6 +229,7 @@ config RISCV
 	select THREAD_INFO_IN_TASK
 	select TRACE_IRQFLAGS_SUPPORT
 	select UACCESS_MEMCPY if !MMU
+	select VDSO_CHECK if MMU
 	select VDSO_DATASTORE if MMU
 	select VDSO_GETRANDOM if MMU && 64BIT
 	select USER_STACKTRACE_SUPPORT
diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile
index 8dbf2532a573..7e707fdff26c 100644
--- a/arch/riscv/kernel/vdso/Makefile
+++ b/arch/riscv/kernel/vdso/Makefile
@@ -74,7 +74,7 @@ endif
 $(obj)/$(vdso_o): $(obj)/$(vdso_so)
 
 # link rule for the .so file, .lds has to be first
-$(obj)/$(vdso_so_dbg): $(obj)/$(vdso_lds) $(obj-vdso) FORCE
+$(obj)/$(vdso_so_dbg): $(obj)/$(vdso_lds) $(obj-vdso) $(vdsocheck) FORCE
 	$(call if_changed,vdsold_and_check)
 LDFLAGS_$(vdso_so_dbg) = -shared -soname=linux-vdso.so.1 \
 	--build-id=sha1 --eh-frame-hdr
@@ -96,7 +96,7 @@ include/generated/$(vdso_offsets): $(obj)/$(vdso_so_dbg) FORCE
 # The DSO images are built using a special linker script
 # Make sure only to export the intended __vdso_xxx symbol offsets.
 quiet_cmd_vdsold_and_check = VDSOLD  $@
-      cmd_vdsold_and_check = $(LD) $(CFI_FULL) $(ld_flags) -T $(filter-out FORCE,$^) -o $@.tmp && \
+      cmd_vdsold_and_check = $(LD) $(CFI_FULL) $(ld_flags) -T $(filter-out FORCE $(vdsocheck),$^) -o $@.tmp && \
                    $(OBJCOPY) $(patsubst %, -G __vdso_%, $(vdso-syms)) $@.tmp $@ && \
                    rm $@.tmp && \
                    $(cmd_vdso_check)
diff --git a/lib/vdso/check/vdsocheck.rs b/lib/vdso/check/vdsocheck.rs
index 429bdcd65818..67562d21f877 100644
--- a/lib/vdso/check/vdsocheck.rs
+++ b/lib/vdso/check/vdsocheck.rs
@@ -96,6 +96,32 @@ fn allowed_relocations_for_machine(machine: u16) -> Option<AllowedRelocations<'s
             ..Default::default()
         }
         .into(),
+        bindings::EM_RISCV => AllowedRelocations {
+            in_object_file: &[
+                bindings::R_RISCV_BRANCH,
+                bindings::R_RISCV_JAL,
+                bindings::R_RISCV_CALL,
+                bindings::R_RISCV_CALL_PLT,
+                bindings::R_RISCV_PCREL_HI20,
+                bindings::R_RISCV_PCREL_LO12_I,
+                bindings::R_RISCV_PCREL_LO12_S,
+                bindings::R_RISCV_ADD8,
+                bindings::R_RISCV_ADD16,
+                bindings::R_RISCV_ADD32,
+                bindings::R_RISCV_ADD64,
+                bindings::R_RISCV_SUB8,
+                bindings::R_RISCV_SUB16,
+                bindings::R_RISCV_SUB32,
+                bindings::R_RISCV_SUB64,
+                bindings::R_RISCV_ALIGN,
+                bindings::R_RISCV_RVC_BRANCH,
+                bindings::R_RISCV_RVC_JUMP,
+                bindings::R_RISCV_RELAX,
+                bindings::R_RISCV_32_PCREL,
+            ],
+            ..Default::default()
+        }
+        .into(),
         _ => None,
     }
 }

-- 
2.55.0