Wipe stack related changes

Author: mekosko

riscv-rt/src/asm.rs

@@ -125,7 +125,6 @@ cfg_global_asm!(
 );
 
 // STORE A0..A2 IN THE STACK, AS THEY WILL BE NEEDED LATER BY main
-#[cfg(not(feature = "u-boot"))]
 cfg_global_asm!(
     #[cfg(riscv32)]
     "addi sp, sp, -4 * 3
@@ -214,12 +213,12 @@ riscv_rt_macros::loop_global_asm!("    fmv.w.x f{}, x0", 32);
 // SET UP INTERRUPTS, RESTORE a0..a2, AND JUMP TO MAIN RUST FUNCTION
 cfg_global_asm!(
     "call _setup_interrupts",
-    #[cfg(all(riscv32, not(feature = "u-boot")))]
+    #[cfg(riscv32)]
     "lw a0, 4 * 0(sp)
     lw a1, 4 * 1(sp)
     lw a2, 4 * 2(sp)
     addi sp, sp, 4 * 3",
-    #[cfg(all(riscv64, not(feature = "u-boot")))]
+    #[cfg(riscv64)]
     "ld a0, 8 * 0(sp)
     ld a1, 8 * 1(sp)
     ld a2, 8 * 2(sp)

riscv-rt/src/lib.rs

@@ -452,20 +452,19 @@
 //! ```
 //!
 //! This will generate a function named `_start_MachineTimer_trap` that calls the interrupt handler `MachineTimer`.
-//! 
+//!
 //! ## `u-boot`
-//! 
+//!
 //! The u-boot support feature (`u-boot`) can be activated via [Cargo features](https://doc.rust-lang.org/cargo/reference/features.html).
-//! 
+//!
 //! For example:
 //! ``` text
 //! [dependencies]
 //! riscv-rt = { features = ["u-boot"] }
 //! ```
-//! When the u-boot feature is enabled, some assembly code is disabled to leave stack untouched. This is required
-//! because when booting from elf, u-boot passes arguments as argc and argv through stack. Because the only way
-//! to get boot-hart is through fdt, this feature also implies `single-hart` so other harts initialization
-//! is up to you.
+//! When the u-boot feature is enabled, acceptable signature for `#[entry]` macros is changed. This is required
+//! because when booting from elf, u-boot passes `argc` and `argv`. This feature also implies `single-hart`.
+//! The only way to get boot-hart is through fdt, so other harts initialization is up to you.
 
 // NOTE: Adapted from cortex-m/src/lib.rs
 #![no_std]