feat: better rtc framework which aims to remove single rtc restrictions.

[lunaix-os.git] / lunaix-os / hal / rng / rngx86.c

diff --git a/lunaix-os/hal/rng/rngx86.c b/lunaix-os/hal/rng/rngx86.c
new file mode 100644 (file)
index 0000000..aea9b69
--- /dev/null
+++ b/lunaix-os/hal/rng/rngx86.c
@@ -0,0 +1,38 @@
+#include <lunaix/device.h>
+#include <lunaix/mm/page.h>
+
+static inline void
+rng_fill(void* data, size_t len)
+{
+    asm volatile("1:\n"
+                 "rdrand %%eax\n"
+                 "movl %%eax, (%0)\n"
+                 "addl $4, %%eax\n"
+                 "subl $4, %1\n"
+                 "jnz 1b" ::"r"((ptr_t)data),
+                 "r"((len & ~0x3))
+                 : "%eax");
+}
+
+static int
+__rand_rd_pg(struct device* dev, void* buf, size_t offset)
+{
+    rng_fill(buf, PG_SIZE);
+    return PG_SIZE;
+}
+
+static int
+__rand_rd(struct device* dev, void* buf, size_t offset, size_t len)
+{
+    rng_fill(buf, len);
+    return len;
+}
+
+void
+pdev_randdev_init()
+{
+    struct device* devrand = device_addseq(NULL, NULL, "rand");
+    devrand->ops.read = __rand_rd;
+    devrand->ops.read_page = __rand_rd_pg;
+}
+EXPORT_PSEUDODEV(randdev, pdev_randdev_init);
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