RISC-V: Add support for rv32 userspace via COMPAT

[sfrench/cifs-2.6.git] / arch / riscv / Kconfig

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index d085846812160fc87f60998dca7479be319d18d1..cad2d42a77d9d8509b2fac6680474c232af49d43 100644 (file)
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -76,6 +76,7 @@ config RISCV
        select HAVE_ARCH_KGDB if !XIP_KERNEL
        select HAVE_ARCH_KGDB_QXFER_PKT
        select HAVE_ARCH_MMAP_RND_BITS if MMU
+       select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
        select HAVE_ARCH_SECCOMP_FILTER
        select HAVE_ARCH_TRACEHOOK
        select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT && MMU
@@ -127,12 +128,18 @@ config ARCH_MMAP_RND_BITS_MIN
        default 18 if 64BIT
        default 8
 
+config ARCH_MMAP_RND_COMPAT_BITS_MIN
+       default 8
+
 # max bits determined by the following formula:
 #  VA_BITS - PAGE_SHIFT - 3
 config ARCH_MMAP_RND_BITS_MAX
        default 24 if 64BIT # SV39 based
        default 17
 
+config ARCH_MMAP_RND_COMPAT_BITS_MAX
+       default 17
+
 # set if we run in machine mode, cleared if we run in supervisor mode
 config RISCV_M_MODE
        bool
@@ -422,6 +429,18 @@ config CRASH_DUMP
 
          For more details see Documentation/admin-guide/kdump/kdump.rst
 
+config COMPAT
+       bool "Kernel support for 32-bit U-mode"
+       default 64BIT
+       depends on 64BIT && MMU
+       help
+         This option enables support for a 32-bit U-mode running under a 64-bit
+         kernel at S-mode. riscv32-specific components such as system calls,
+         the user helper functions (vdso), signal rt_frame functions and the
+         ptrace interface are handled appropriately by the kernel.
+
+         If you want to execute 32-bit userspace applications, say Y.
+
 endmenu
 
 menu "Boot options"