Commit 91bf6955 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/vdso: Retrieve sigtramp offsets at buildtime 



This is copied from arm64.

Instead of using runtime generated signal trampoline offsets,
get offsets at buildtime.

If the said trampoline doesn't exist, build will fail. So no
need to check whether the trampoline exists or not in the VDSO.

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/f8bfd6812c3e3678b1cdb4d55a52f9eb022b40d3.1601197618.git.christophe.leroy@csgroup.eu
parent 550e6074

arch/powerpc/Makefile

+15 −0
Original line number Diff line number Diff line
@@ -409,6 +409,21 @@ install: 
archclean:

	$(Q)$(MAKE) $(clean)=$(boot)



ifeq ($(KBUILD_EXTMOD),)

# We need to generate vdso-offsets.h before compiling certain files in kernel/.

# In order to do that, we should use the archprepare target, but we can't since

# asm-offsets.h is included in some files used to generate vdso-offsets.h, and

# asm-offsets.h is built in prepare0, for which archprepare is a dependency.

# Therefore we need to generate the header after prepare0 has been made, hence

# this hack.

prepare: vdso_prepare

vdso_prepare: prepare0

	$(if $(CONFIG_VDSO32),$(Q)$(MAKE) \

		$(build)=arch/powerpc/kernel/vdso32 include/generated/vdso32-offsets.h)

	$(if $(CONFIG_PPC64),$(Q)$(MAKE) \

		$(build)=arch/powerpc/kernel/vdso64 include/generated/vdso64-offsets.h)

endif



archprepare: checkbin



archheaders:

arch/powerpc/include/asm/vdso.h

+12 −0
Original line number Diff line number Diff line
@@ -15,6 +15,18 @@ 


#ifndef __ASSEMBLY__



#ifdef CONFIG_PPC64

#include <generated/vdso64-offsets.h>

#endif



#ifdef CONFIG_VDSO32

#include <generated/vdso32-offsets.h>

#endif



#define VDSO64_SYMBOL(base, name) ((unsigned long)(base) + (vdso64_offset_##name))



#define VDSO32_SYMBOL(base, name) ((unsigned long)(base) + (vdso32_offset_##name))



/* Offsets relative to thread->vdso_base */

extern unsigned long vdso64_rt_sigtramp;

extern unsigned long vdso32_sigtramp;

arch/powerpc/kernel/signal_32.c

+4 −4
Original line number Diff line number Diff line
@@ -801,8 +801,8 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset, 
	}



	/* Save user registers on the stack */

	if (vdso32_rt_sigtramp && tsk->mm->context.vdso) {

		tramp = (unsigned long)tsk->mm->context.vdso + vdso32_rt_sigtramp;

	if (tsk->mm->context.vdso) {

		tramp = VDSO32_SYMBOL(tsk->mm->context.vdso, sigtramp_rt32);

	} else {

		tramp = (unsigned long)mctx->mc_pad;

		/* Set up the sigreturn trampoline: li r0,sigret; sc */
@@ -901,8 +901,8 @@ int handle_signal32(struct ksignal *ksig, sigset_t *oldset, 
	else

		unsafe_save_user_regs(regs, mctx, tm_mctx, 1, failed);



	if (vdso32_sigtramp && tsk->mm->context.vdso) {

		tramp = (unsigned long)tsk->mm->context.vdso + vdso32_sigtramp;

	if (tsk->mm->context.vdso) {

		tramp = VDSO32_SYMBOL(tsk->mm->context.vdso, sigtramp32);

	} else {

		tramp = (unsigned long)mctx->mc_pad;

		/* Set up the sigreturn trampoline: li r0,sigret; sc */

arch/powerpc/kernel/signal_64.c

+2 −2
Original line number Diff line number Diff line
@@ -854,8 +854,8 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set, 
	tsk->thread.fp_state.fpscr = 0;



	/* Set up to return from userspace. */

	if (vdso64_rt_sigtramp && tsk->mm->context.vdso) {

		regs->nip = (unsigned long)tsk->mm->context.vdso + vdso64_rt_sigtramp;

	if (tsk->mm->context.vdso) {

		regs->nip = VDSO64_SYMBOL(tsk->mm->context.vdso, sigtramp_rt64);

	} else {

		err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]);

		if (err)

arch/powerpc/kernel/vdso32/Makefile

+8 −0
Original line number Diff line number Diff line
@@ -59,6 +59,14 @@ $(obj-vdso32): %.o: %.S FORCE 
$(obj)/vgettimeofday.o: %.o: %.c FORCE

	$(call if_changed_dep,vdso32cc)



# Generate VDSO offsets using helper script

gen-vdsosym := $(srctree)/$(src)/gen_vdso_offsets.sh

quiet_cmd_vdsosym = VDSOSYM $@

      cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@



include/generated/vdso32-offsets.h: $(obj)/vdso32.so.dbg FORCE

	$(call if_changed,vdsosym)



# actual build commands

quiet_cmd_vdso32ld_and_check = VDSO32L $@

      cmd_vdso32ld_and_check = $(VDSOCC) $(c_flags) $(CC32FLAGS) -o $@ -Wl,-T$(filter %.lds,$^) $(filter %.o,$^) ; $(cmd_vdso_check)