daemon: Add support for UIO-based SR0

The GateMP daemon uses /dev/mem to access SR0, where the gate
usage arrays are kept.  /dev/mem may not be present in all
production systems due to the security risk that it implies.

A userspace I/O driver approach can be used as an alternative.
The Linux kernel needs to expose a UIO named 'sr0' in order
to access the shared region from userspace.  The daemon is now
capable of finding such UIO entry if exists, and otherwise
fall back to the previous /dev/mem based approach.

Signed-off-by: Misael Lopez Cruz <misael.lopez@ti.com>

diff --git a/linux/src/daemon/GateMP_daemon.c b/linux/src/daemon/GateMP_daemon.c
index 7e689d1634e06a11f2b3176205ff67bf5c1b370d..f66a28cd9b7eab9ef39952476d1272d9f029cb65 100644 (file)
--- a/linux/src/daemon/GateMP_daemon.c
+++ b/linux/src/daemon/GateMP_daemon.c
@@ -47,6 +47,9 @@
 #include <fcntl.h>
 #include <stdlib.h>
 #include <assert.h>
+#include <dirent.h>
+#include <errno.h>
+#include <string.h>
 
 /* Module level headers */
 #include <ti/ipc/GateMP.h>
@@ -74,6 +77,9 @@ extern "C" {
 /* Name of GateMP's nameserver */
 #define GateMP_NAMESERVER  "GateMP"
 
+/* sysfs path for the UIO user-space drivers */
+#define UIO_SYSFS          "/sys/class/uio"
+
 #define PAGE_ALIGN(size, psz)  (((size) + psz - 1) & ~(psz -1))
 
 /* =============================================================================
@@ -97,6 +103,7 @@ typedef struct {
 } GateMP_ModuleObject;
 
 /* Internal functions */
+static Int GateMP_get_sr0(Char *name, UInt32 name_len, UInt32 *baseaddr);
 static Int GateMP_openDefaultGate(GateMP_Handle *handlePtr, UInt16 procId[]);
 static Int GateMP_closeDefaultGate(GateMP_Handle *handlePtr);
 
@@ -168,9 +175,11 @@ Int GateMP_attach(UInt16 procId)
     UInt32            size;
     UInt32            alignDiff;
     UInt32            offset;
+    UInt32            baseaddr;
     Int32             fdMem;
     UInt16            procList[2];
     UInt16            clId;
+    Char              filename[PATH_MAX];
 
     /* procId already validated in API layer */
     clId = procId - MultiProc_getBaseIdOfCluster();
@@ -221,10 +230,15 @@ Int GateMP_attach(UInt16 procId)
             status = GateMP_E_NOTFOUND;
         }
         else {
-            fdMem = open ("/dev/mem", O_RDWR | O_SYNC);
+            status = GateMP_get_sr0(filename, PATH_MAX, &baseaddr);
+            if (status < 0) {
+                LOG1("GateMP_attach: failed to find sr0: %s\n", strerror(status));
+                status = GateMP_E_NOTFOUND;
+            }
 
+            fdMem = open (filename, O_RDWR | O_SYNC);
             if (fdMem < 0){
-                LOG0("GateMP_attach: failed to open the /dev/mem!\n");
+                LOG1("GateMP_attach: failed to open the %s!\n", filename);
                 status = GateMP_E_OSFAILURE;
                 goto done;
             }
@@ -238,6 +252,8 @@ Int GateMP_attach(UInt16 procId)
                 (nsValue[0] & (sysconf(_SC_PAGE_SIZE) - 1));
             size = PAGE_ALIGN(size, sysconf(_SC_PAGE_SIZE));
             offset = nsValue[0] & ~(sysconf(_SC_PAGE_SIZE) - 1);
+            offset -= baseaddr;
+
 #if defined(IPC_BUILDOS_ANDROID)
             GateMP_module->remoteSystemInUse = mmap64(NULL, size,
                 (PROT_READ|PROT_WRITE), (MAP_SHARED), fdMem,
@@ -254,7 +270,7 @@ Int GateMP_attach(UInt16 procId)
                  status = GateMP_E_MEMORY;
             }
             else {
-                alignDiff = nsValue[0] - offset;
+                alignDiff = nsValue[0] - baseaddr - offset;
                 GateMP_module->remoteSystemInUse =
                     GateMP_module->remoteSystemInUse + alignDiff;
             }
@@ -263,6 +279,8 @@ Int GateMP_attach(UInt16 procId)
                 (nsValue[1] & (sysconf(_SC_PAGE_SIZE) - 1));
             size = PAGE_ALIGN(size, sysconf(_SC_PAGE_SIZE));
             offset = nsValue[1] & ~(sysconf(_SC_PAGE_SIZE) - 1);
+            offset -= baseaddr;
+
             if (status == GateMP_S_SUCCESS) {
 #if defined(IPC_BUILDOS_ANDROID)
                 GateMP_module->remoteCustom1InUse = mmap64(NULL, size,
@@ -280,7 +298,7 @@ Int GateMP_attach(UInt16 procId)
                     status = GateMP_E_MEMORY;
                 }
                 else {
-                    alignDiff = nsValue[1] - offset;
+                    alignDiff = nsValue[1] - baseaddr - offset;
                     GateMP_module->remoteCustom1InUse =
                         GateMP_module->remoteCustom1InUse + alignDiff;
                 }
@@ -290,6 +308,8 @@ Int GateMP_attach(UInt16 procId)
                 (nsValue[2] & (sysconf(_SC_PAGE_SIZE) - 1));
             size = PAGE_ALIGN(size, sysconf(_SC_PAGE_SIZE));
             offset = nsValue[2] & ~(sysconf(_SC_PAGE_SIZE) - 1);
+            offset -= baseaddr;
+
             if (status == GateMP_S_SUCCESS) {
 #if defined(IPC_BUILDOS_ANDROID)
                 GateMP_module->remoteCustom2InUse = mmap64(NULL, size,
@@ -307,7 +327,7 @@ Int GateMP_attach(UInt16 procId)
                     status = GateMP_E_MEMORY;
                 }
                 else {
-                    alignDiff = nsValue[2] - offset;
+                    alignDiff = nsValue[2] - baseaddr - offset;
                     GateMP_module->remoteCustom2InUse =
                         GateMP_module->remoteCustom2InUse + alignDiff;
                 }
@@ -384,6 +404,87 @@ Void GateMP_destroy(Void)
     return;
 }
 
+static Int GateMP_get_sr0(Char *name, UInt32 name_len, UInt32 *baseaddr)
+{
+    Char filename[PATH_MAX];
+    Char format[80];
+    Char uio_name[80];
+    DIR *dir;
+    struct dirent *de;
+    struct stat st;
+    FILE *fd;
+    Bool found = false;
+    Int ret = 0;
+
+    if (stat(UIO_SYSFS, &st) < 0) {
+        if ((errno == ENOENT) || (errno == ENOTDIR)) {
+            LOG0("GateMP_get_sr0: UIO support not found\n");
+            ret = errno;
+            goto out;
+        }
+    }
+
+    dir = opendir(UIO_SYSFS);
+    if (!dir) {
+        LOG1("GateMP_get_sr0: failed to open UIO sysfs %s\n", UIO_SYSFS);
+        ret = errno;
+        goto out;
+    }
+
+    while (!found) {
+        de = readdir(dir);
+        if (!de) {
+            break;
+        }
+
+        if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) {
+            continue;
+        }
+
+        /* Skip if this is not an UIO entry */
+        snprintf(filename, sizeof(filename), "%s/%s/name", UIO_SYSFS, de->d_name);
+        fd = fopen(filename, "r");
+        if (fd == NULL) {
+            continue;
+        }
+
+        snprintf(format, sizeof(format), "%%%ds", sizeof(uio_name)-1);
+        fscanf(fd, format, uio_name);
+        fclose(fd);
+
+        /* Skip if this UIO entry is not SR0 */
+        if (strncmp(uio_name, "sr0", sizeof(uio_name)-1)) {
+            continue;
+        }
+
+        /* Find the base address of the SR0 UIO */
+        snprintf(filename, sizeof(filename), "%s/%s/maps/map0/addr", UIO_SYSFS, de->d_name);
+        fd = fopen(filename, "r");
+        if (fd == NULL) {
+            LOG0("Gate_sr0_filename: failed to open uio map sysfs\n");
+            ret = errno;
+            break;
+        }
+
+        fscanf(fd, "0x%x", baseaddr);
+        fclose(fd);
+
+        snprintf(name, name_len, "/dev/%s", de->d_name);
+        found = true;
+    }
+
+    closedir(dir);
+
+out:
+    /* Fall back to /dev/mem if UIO is not supported */
+    if (!found) {
+        strncpy(name, "/dev/mem", name_len);
+        baseaddr = 0x0;
+    }
+
+    return ret;
+}
+
 /* Open default gate during GateMP_attach. Should only be called once */
 static Int GateMP_openDefaultGate(GateMP_Handle *handlePtr, UInt16 procId[])
 {