lkmc_vector_equal into lkmc.c

Document lkmc.c

README.adoc

@@ -12990,6 +12990,23 @@ ls /mnt/9p/rootfs_overlay
 
 This way you can just hack away the scripts and try them out immediately without any further operations.
 
+==== lkmc.c
+
+The files:
+
+* link:lkmc.c[]
+* link:lkmc.h[]
+
+contain common C function helpers that can be used both in userland and baremetal. Oh, the infinite <<about-the-baremetal-setup,joys of Newlib>>.
+
+Those files also contain arch specific helpers under ifdefs like:
+
+....
+#if defined(__aarch64__)
+....
+
+We try to keep as much as possible in those files. It bloats builds a little, but just makes everything simpler to understand.
+
 === Test this repo
 
 ==== Automated tests

baremetal/lib/aarch64.S

@@ -23,7 +23,7 @@ LKMC_VECTOR_TABLE
 
 /* Default trap handler that does nothing.
  *
- * Weak means that if any other file deinfes it as a non-weak global,
+ * Weak means that if any other file defines it as a non-weak global,
  * that one will take precedence.
  *
  * We need this one to not get undefined references.

build-baremetal

@@ -19,9 +19,7 @@ Build the baremetal examples with crosstool-NG.
     def build(self):
         build_dir = self.get_build_dir()
         bootloader_obj = os.path.join(self.env['baremetal_build_lib_dir'], 'bootloader{}'.format(self.env['obj_ext']))
-        common_basename_noext = 'lkmc'
+        common_obj = os.path.join(self.env['baremetal_build_lib_dir'], self.env['common_basename_noext'] + self.env['obj_ext'])
-        common_src = os.path.join(self.env['root_dir'], common_basename_noext + self.env['c_ext'])
-        common_obj = os.path.join(self.env['baremetal_build_lib_dir'], common_basename_noext + self.env['obj_ext'])
         syscalls_basename_noext = 'syscalls'
         syscalls_src = os.path.join(self.env['baremetal_source_lib_dir'], syscalls_basename_noext + self.env['c_ext'])
         syscalls_obj = os.path.join(self.env['baremetal_build_lib_dir'], syscalls_basename_noext + self.env['obj_ext'])
@@ -34,6 +32,7 @@ Build the baremetal examples with crosstool-NG.
             '-mcpu={}'.format(self.env['mcpu']), LF,
             '-nostartfiles', LF,
         ]
+        cflags_after = ['-lm']
         gcc = self.get_toolchain_tool('gcc')
         if self.env['emulator'] == 'gem5':
             if self.env['machine'] == 'VExpress_GEM5_V1':
@@ -59,10 +58,11 @@ Build the baremetal examples with crosstool-NG.
                     '-c', LF,
                     '-o', bootloader_obj, LF,
                     src, LF,
-                ]
+                ] +
+                cflags_after
             )
         for src, obj in [
-            (common_src, common_obj),
+            (self.env['common_c'], common_obj),
             (syscalls_src, syscalls_obj),
         ]:
             if self.need_rebuild([src], obj):
@@ -74,12 +74,14 @@ Build the baremetal examples with crosstool-NG.
                         '-D', 'UART0_ADDR={:#x}'.format(uart_address), LF,
                         '-o', obj, LF,
                         src, LF,
-                    ]
+                    ] +
+                    cflags_after
                 )
         self._build_dir(
             '',
             gcc=gcc,
             cflags=cflags,
+            cflags_after=cflags_after,
             entry_address=entry_address,
             bootloader_obj=bootloader_obj,
             common_objs=common_objs,
@@ -88,6 +90,7 @@ Build the baremetal examples with crosstool-NG.
             'interactive',
             gcc=gcc,
             cflags=cflags,
+            cflags_after=cflags_after,
             entry_address=entry_address,
             bootloader_obj=bootloader_obj,
             common_objs=common_objs,
@@ -97,6 +100,7 @@ Build the baremetal examples with crosstool-NG.
                 self.env['baremetal_source_arch_subpath'],
                 gcc=gcc,
                 cflags=cflags,
+                cflags_after=cflags_after,
                 entry_address=entry_address,
                 bootloader_obj=bootloader_obj,
                 common_objs=common_objs,
@@ -107,6 +111,7 @@ Build the baremetal examples with crosstool-NG.
                 arch_dir,
                 gcc=gcc,
                 cflags=cflags,
+                cflags_after=cflags_after,
                 entry_address=entry_address,
                 bootloader_obj=bootloader_obj,
                 common_objs=common_objs,
@@ -121,6 +126,7 @@ Build the baremetal examples with crosstool-NG.
             subpath,
             gcc,
             cflags,
+            cflags_after,
             entry_address,
             bootloader_obj,
             common_objs,
@@ -152,7 +158,8 @@ Build the baremetal examples with crosstool-NG.
                             '-c', LF,
                             '-o', main_obj, LF,
                             src, LF,
-                        ]
+                        ] +
+                        cflags_after
                     )
                 objs = common_objs + [main_obj]
                 out = os.path.join(self.env['baremetal_build_dir'], subpath, in_name + self.env['baremetal_build_ext'])
@@ -166,7 +173,8 @@ Build the baremetal examples with crosstool-NG.
                             '-o', out, LF,
                             '-T', link_script, LF,
                         ] +
-                        self.sh.add_newlines(objs)
+                        self.sh.add_newlines(objs) +
+                        cflags_after
                     )
 
 if __name__ == '__main__':

common.py

@@ -726,6 +726,17 @@ Valid emulators: {}
         env['baremetal_build_lib_dir'] = join(env['baremetal_build_dir'], env['baremetal_lib_basename'])
         env['baremetal_build_ext'] = '.elf'
 
+        # Userland / baremetal common source.
+        env['common_basename_noext'] = 'lkmc'
+        env['common_c'] = common_c = os.path.join(
+            env['root_dir'],
+            env['common_basename_noext'] + env['c_ext']
+        )
+        env['common_h'] = common_c = os.path.join(
+            env['root_dir'],
+            env['common_basename_noext'] + env['header_ext']
+        )
+
         # Docker
         env['docker_build_dir'] = join(env['out_dir'], 'docker', env['arch'])
         env['docker_tar_dir'] = join(env['docker_build_dir'], 'export')

lkmc.c

@@ -1,3 +1,6 @@
+/* https://github.com/cirosantilli/linux-kernel-module-cheat#lkmc-c */
+
+#include <math.h>
 #include <stdio.h>
 #include <stdlib.h>
 
@@ -13,6 +16,19 @@ void lkmc_assert_fail() {
     exit(1);
 }
 
+bool lkmc_vector_equal(size_t n, double *v1, double *v2, double max_err) {
+    double sum = 0.0;
+    double diff;
+    size_t i;
+    for (i = 0; i < n; ++i) {
+        diff = v1[i] - v2[i];
+        sum += diff * diff;
+    }
+    if (sqrt(sum)/n > max_err)
+        return false;
+    return true;
+}
+
 #if defined(__aarch64__)
 #define LKMC_SYSREG_READ_WRITE(type, name) \
     type LKMC_CONCAT(LKMC_CONCAT(LKMC_SYSREG_SYMBOL_PREFIX, name), _read(void)) { \

lkmc.h

@@ -1,13 +1,17 @@
+/* https://github.com/cirosantilli/linux-kernel-module-cheat#lkmc-c */
+
 #ifndef LKMC_H
 #define LKMC_H
 
 /* Common C definitions. */
 #if !defined(__ASSEMBLER__)
-#include <stdbool.h>
 #include <inttypes.h>
+#include <stdbool.h>
+#include <stdlib.h>
 
 void lkmc_assert(bool);
 void lkmc_assert_fail();
+bool lkmc_vector_equal(size_t n, double *v1, double *v2, double max_err);
 #endif
 
 /* https://stackoverflow.com/questions/1489932/how-to-concatenate-twice-with-the-c-preprocessor-and-expand-a-macro-as-in-arg */

userland/common_userland.h

@@ -3,13 +3,10 @@
 
 #define _XOPEN_SOURCE 700
 #include <fcntl.h> /* open */
-#include <math.h> /* fabs */
 #include <stdint.h> /* uint64_t  */
-#include <stdlib.h> /* size_t */
 #include <stdio.h> /* snprintf */
 #include <sys/types.h>
 #include <unistd.h> /* pread, sysconf */
-#include <stdbool.h>
 
 /* Format documented at:
  * https://github.com/torvalds/linux/blob/v4.9/Documentation/vm/pagemap.txt
@@ -84,18 +81,4 @@ int virt_to_phys_user(uintptr_t *paddr, pid_t pid, uintptr_t vaddr)
     return 0;
 }
 
-bool common_vector_equal(size_t n, double * v1, double * v2, double max_err)
-{
-	double sum = 0.0;
-	double diff;
-	size_t i;
-	for (i = 0; i < n; ++i) {
-		diff = v1[i] - v2[i];
-		sum += diff * diff;
-	}
-	if (sqrt(sum)/n > max_err)
-		return false;
-	return true;
-}
-
 #endif

userland/openblas_hello.c

@@ -1,16 +1,15 @@
 /* https://github.com/cirosantilli/linux-kernel-module-cheat#blas
  * Adapted from: https://github.com/xianyi/OpenBLAS/wiki/User-Manual/59b62f98e7400270fb03ad1d85fba5b64ebbff2b#call-cblas-interface */
 
-#include "common_userland.h"
+#include "lkmc.h"
 
 #include <assert.h>
 #include <cblas.h>
 
-int main(void)
+int main(void) {
-{
     double A[6] = {1.0, 2.0, 1.0, -3.0, 4.0, -1.0};
     double B[6] = {1.0, 2.0, 1.0, -3.0, 4.0, -1.0};
     double C[9] = {0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5};
     cblas_dgemm(CblasColMajor, CblasNoTrans, CblasTrans, 3, 3, 2, 1, A, 3, B, 3, 2, C, 3);
-	assert(common_vector_equal(9, C, (double[]){11.0, -9.0, 5.0, -9.0, 21.0, -1.0, 5.0, -1.0, 3.0}, 1e-6));
+    assert(lkmc_vector_equal(9, C, (double[]){11.0, -9.0, 5.0, -9.0, 21.0, -1.0, 5.0, -1.0, 3.0}, 1e-6));
 }