From: Kevin Brodsky <kevin.brodsky@arm.com>
Date: Thu, 12 May 2016 09:55:47 +0000 (+0100)
Subject: FROMLIST: [PATCH 1/6] arm64: compat: Use vDSO sigreturn trampolines if available
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=6a6a90db779e45ea8dad30fed700178970ae01b1;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git

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 839ce0031bd5..f2a952338f1e 100644
--- 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 7f6031da15fc..666363d127e5 100644
--- 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;