arch: Reserve map_shadow_stack() syscall number for all architectures

sohilmeh · arndb · commit 2fd0ebad27bc · 2023-10-06T22:26:51.000+02:00
commit c35559f ("x86/shstk: Introduce map_shadow_stack syscall") recently added support for map_shadow_stack() but it is limited to x86 only for now. There is a possibility that other architectures (namely, arm64 and RISC-V), that are implementing equivalent support for shadow stacks, might need to add support for it. Independent of that, reserving arch-specific syscall numbers in the syscall tables of all architectures is good practice and would help avoid future conflicts. map_shadow_stack() is marked as a conditional syscall in sys_ni.c. Adding it to the syscall tables of other architectures is harmless and would return ENOSYS when exercised. Note, map_shadow_stack() was assigned #453 during the merge process since torvalds#452 was taken by fchmodat2(). For Powerpc, map it to sys_ni_syscall() as is the norm for Powerpc syscall tables. For Alpha, map_shadow_stack() takes up torvalds#563 as Alpha still diverges from the common syscall numbering system in the other architectures. Link: https://lore.kernel.org/lkml/20230515212255.GA562920@debug.ba.rivosinc.com/ Link: https://lore.kernel.org/lkml/b402b80b-a7c6-4ef0-b977-c0f5f582b78a@sirena.org.uk/ Signed-off-by: Sohil Mehta <sohil.mehta@intel.com> Reviewed-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl
@@ -492,3 +492,4 @@
 560	common	set_mempolicy_home_node		sys_ni_syscall
 561	common	cachestat			sys_cachestat
 562	common	fchmodat2			sys_fchmodat2
+563	common	map_shadow_stack		sys_map_shadow_stack
diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
@@ -466,3 +466,4 @@
 450	common	set_mempolicy_home_node		sys_set_mempolicy_home_node
 451	common	cachestat			sys_cachestat
 452	common	fchmodat2			sys_fchmodat2
+453	common	map_shadow_stack		sys_map_shadow_stack
diff --git a/arch/arm64/include/asm/unistd.h b/arch/arm64/include/asm/unistd.h
@@ -39,7 +39,7 @@
 #define __ARM_NR_compat_set_tls		(__ARM_NR_COMPAT_BASE + 5)
 #define __ARM_NR_COMPAT_END		(__ARM_NR_COMPAT_BASE + 0x800)
 
-#define __NR_compat_syscalls		453
+#define __NR_compat_syscalls		454
 #endif
 
 #define __ARCH_WANT_SYS_CLONE
diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
@@ -911,6 +911,8 @@ __SYSCALL(__NR_set_mempolicy_home_node, sys_set_mempolicy_home_node)
 __SYSCALL(__NR_cachestat, sys_cachestat)
 #define __NR_fchmodat2 452
 __SYSCALL(__NR_fchmodat2, sys_fchmodat2)
+#define __NR_map_shadow_stack 453
+__SYSCALL(__NR_map_shadow_stack, sys_map_shadow_stack)
 
 /*
  * Please add new compat syscalls above this comment and update
diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl
@@ -452,3 +452,4 @@
 450	common	set_mempolicy_home_node		sys_set_mempolicy_home_node
 451	common	cachestat			sys_cachestat
 452	common	fchmodat2			sys_fchmodat2
+453	common	map_shadow_stack		sys_map_shadow_stack
diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl
@@ -458,3 +458,4 @@
 450	common	set_mempolicy_home_node		sys_set_mempolicy_home_node
 451	common	cachestat			sys_cachestat
 452	common	fchmodat2			sys_fchmodat2
+453	common	map_shadow_stack		sys_map_shadow_stack
diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
@@ -391,3 +391,4 @@
 450	n32	set_mempolicy_home_node		sys_set_mempolicy_home_node
 451	n32	cachestat			sys_cachestat
 452	n32	fchmodat2			sys_fchmodat2
+453	n32	map_shadow_stack		sys_map_shadow_stack
diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl
@@ -367,3 +367,4 @@
 450	common	set_mempolicy_home_node		sys_set_mempolicy_home_node
 451	n64	cachestat			sys_cachestat
 452	n64	fchmodat2			sys_fchmodat2
+453	n64	map_shadow_stack		sys_map_shadow_stack
diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
@@ -440,3 +440,4 @@
 450	o32	set_mempolicy_home_node		sys_set_mempolicy_home_node
 451	o32	cachestat			sys_cachestat
 452	o32	fchmodat2			sys_fchmodat2
+453	o32	map_shadow_stack		sys_map_shadow_stack
diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
@@ -451,3 +451,4 @@
 450	common	set_mempolicy_home_node		sys_set_mempolicy_home_node
 451	common	cachestat			sys_cachestat
 452	common	fchmodat2			sys_fchmodat2
+453	common	map_shadow_stack		sys_map_shadow_stack
diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -539,3 +539,4 @@
 450 	nospu	set_mempolicy_home_node		sys_set_mempolicy_home_node
 451	common	cachestat			sys_cachestat
 452	common	fchmodat2			sys_fchmodat2
+453	common	map_shadow_stack		sys_ni_syscall
diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
@@ -455,3 +455,4 @@
 450  common	set_mempolicy_home_node	sys_set_mempolicy_home_node	sys_set_mempolicy_home_node
 451  common	cachestat		sys_cachestat			sys_cachestat
 452  common	fchmodat2		sys_fchmodat2			sys_fchmodat2
+453  common	map_shadow_stack	sys_map_shadow_stack		sys_map_shadow_stack
diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl
@@ -455,3 +455,4 @@
 450	common	set_mempolicy_home_node		sys_set_mempolicy_home_node
 451	common	cachestat			sys_cachestat
 452	common	fchmodat2			sys_fchmodat2
+453	common	map_shadow_stack		sys_map_shadow_stack
diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
@@ -498,3 +498,4 @@
 450	common	set_mempolicy_home_node		sys_set_mempolicy_home_node
 451	common	cachestat			sys_cachestat
 452	common	fchmodat2			sys_fchmodat2
+453	common	map_shadow_stack		sys_map_shadow_stack
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -457,3 +457,4 @@
 450	i386	set_mempolicy_home_node		sys_set_mempolicy_home_node
 451	i386	cachestat		sys_cachestat
 452	i386	fchmodat2		sys_fchmodat2
+453	i386	map_shadow_stack	sys_map_shadow_stack
diff --git a/arch/xtensa/kernel/syscalls/syscall.tbl b/arch/xtensa/kernel/syscalls/syscall.tbl
@@ -423,3 +423,4 @@
 450	common	set_mempolicy_home_node		sys_set_mempolicy_home_node
 451	common	cachestat			sys_cachestat
 452	common	fchmodat2			sys_fchmodat2
+453	common	map_shadow_stack		sys_map_shadow_stack
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
@@ -823,8 +823,11 @@ __SYSCALL(__NR_cachestat, sys_cachestat)
 #define __NR_fchmodat2 452
 __SYSCALL(__NR_fchmodat2, sys_fchmodat2)
 
+#define __NR_map_shadow_stack 453
+__SYSCALL(__NR_map_shadow_stack, sys_map_shadow_stack)
+
 #undef __NR_syscalls
-#define __NR_syscalls 453
+#define __NR_syscalls 454
 
 /*
  * 32 bit systems traditionally used different
