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Subject[RFC PATCH 5/7] x86/mm/fault: hook up SCI verification
Date
If a system call runs in isolated context, it's accesses to kernel code and
data will be verified by SCI susbsytem.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
---
arch/x86/mm/fault.c | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 9d5c75f..baa2a2f 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -18,6 +18,7 @@
#include <linux/uaccess.h> /* faulthandler_disabled() */
#include <linux/efi.h> /* efi_recover_from_page_fault()*/
#include <linux/mm_types.h>
+#include <linux/sci.h> /* sci_verify_and_map() */

#include <asm/cpufeature.h> /* boot_cpu_has, ... */
#include <asm/traps.h> /* dotraplinkage, ... */
@@ -1254,6 +1255,30 @@ static int fault_in_kernel_space(unsigned long address)
return address >= TASK_SIZE_MAX;
}

+#ifdef CONFIG_SYSCALL_ISOLATION
+static int sci_fault(struct pt_regs *regs, unsigned long hw_error_code,
+ unsigned long address)
+{
+ struct task_struct *tsk = current;
+
+ if (!tsk->in_isolated_syscall)
+ return 0;
+
+ if (!sci_verify_and_map(regs, address, hw_error_code)) {
+ this_cpu_write(cpu_sci.sci_syscall, 0);
+ no_context(regs, hw_error_code, address, SIGKILL, 0);
+ }
+
+ return 1;
+}
+#else
+static inline int sci_fault(struct pt_regs *regs, unsigned long hw_error_code,
+ unsigned long address)
+{
+ return 0;
+}
+#endif
+
/*
* Called for all faults where 'address' is part of the kernel address
* space. Might get called for faults that originate from *code* that
@@ -1301,6 +1326,9 @@ do_kern_addr_fault(struct pt_regs *regs, unsigned long hw_error_code,
if (kprobes_fault(regs))
return;

+ if (sci_fault(regs, hw_error_code, address))
+ return;
+
/*
* Note, despite being a "bad area", there are quite a few
* acceptable reasons to get here, such as erratum fixups
--
2.7.4
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