FROMLIST: [PATCH 1/6] arm64: compat: Use vDSO sigreturn trampolines if available

(cherry pick from url https://patchwork.kernel.org/patch/10060449/)

If the compat vDSO is enabled, it replaces the sigreturn page.
Therefore, we use the sigreturn trampolines the vDSO provides instead.

Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Signed-off-by: Mark Salyzyn <salyzyn@android.com>
Bug: 63737556
Bug: 20045882
Change-Id: Ic0933741e321e1bf66409b7e190a776f12948024

diff --git a/arch/arm64/include/asm/vdso.h b/arch/arm64/include/asm/vdso.h
index 839ce0031bd58a076893e844aa12c9a8ed4d33aa..f2a952338f1ef456ab5df6670e98bcf1143976c1 100644 (file)
--- a/arch/arm64/include/asm/vdso.h
+++ b/arch/arm64/include/asm/vdso.h
@@ -28,6 +28,9 @@
 #ifndef __ASSEMBLY__
 
 #include <generated/vdso-offsets.h>
+#ifdef CONFIG_VDSO32
+#include <generated/vdso32-offsets.h>
+#endif
 
 #define VDSO_SYMBOL(base, name)                                                   \
 ({                                                                        \

diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c
index 7f6031da15fcd8167cb9d1b594c2c4927653d997..666363d127e53bf2e0e401cf1d64b5ad03d9849f 100644 (file)
--- a/arch/arm64/kernel/signal32.c
+++ b/arch/arm64/kernel/signal32.c
@@ -28,6 +28,7 @@
 #include <asm/signal32.h>
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
+#include <asm/vdso.h>
 
 struct compat_vfp_sigframe {
        compat_ulong_t  magic;
@@ -438,6 +439,19 @@ static void compat_setup_return(struct pt_regs *regs, struct k_sigaction *ka,
                retcode = ptr_to_compat(ka->sa.sa_restorer);
        } else {
                /* Set up sigreturn pointer */
+#ifdef CONFIG_VDSO32
+               void *vdso_base = current->mm->context.vdso;
+               void *trampoline =
+                       (ka->sa.sa_flags & SA_SIGINFO
+                        ? (thumb
+                           ? VDSO_SYMBOL(vdso_base, compat_rt_sigreturn_thumb)
+                           : VDSO_SYMBOL(vdso_base, compat_rt_sigreturn_arm))
+                        : (thumb
+                           ? VDSO_SYMBOL(vdso_base, compat_sigreturn_thumb)
+                           : VDSO_SYMBOL(vdso_base, compat_sigreturn_arm)));
+
+               retcode = ptr_to_compat(trampoline) + thumb;
+#else
                void *sigreturn_base = current->mm->context.vdso;
                unsigned int idx = thumb << 1;
 
@@ -445,6 +459,7 @@ static void compat_setup_return(struct pt_regs *regs, struct k_sigaction *ka,
                        idx += 3;
 
                retcode = ptr_to_compat(sigreturn_base) + (idx << 2) + thumb;
+#endif
        }
 
        regs->regs[0]   = usig;