Backtrace tweaks (#4012)

* Disallow multiple halt methods

* Warn for nonsense config

* Use DRAM range from metadata

esp-backtrace/CHANGELOG.md

@@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - `exception-handler` now panics. (#3838)
 - Only halt cores in panics when `halt-cores` feature is enabled. (#4010)
+- It is no longer possible to select multiple halt method features (`halt-cores`, `custom-halt`, `semihosting`) (#4012)
 
 ### Fixed
 

esp-backtrace/Cargo.toml

@@ -23,6 +23,7 @@ cfg-if      = "1.0.0"
 critical-section = "1.1.2"
 defmt       = { version = "1", optional = true }
 esp-config  = { version = "0.5.0", path = "../esp-config" }
+esp-metadata-generated = { version = "0.1.0", path = "../esp-metadata-generated" }
 esp-println = { version = "0.15.0", optional = true, default-features = false, path = "../esp-println" }
 heapless    = "0.8"
 semihosting = { version = "0.1.20", optional = true }
@@ -34,13 +35,13 @@ esp-config   = { version = "0.5.0", path = "../esp-config", features = ["build"]
 [features]
 default = ["colors"]
 
-esp32   = ["esp-println?/esp32", "semihosting?/openocd-semihosting", "print-float-registers"]
-esp32c2 = ["esp-println?/esp32c2"]
-esp32c3 = ["esp-println?/esp32c3"]
-esp32c6 = ["esp-println?/esp32c6"]
-esp32h2 = ["esp-println?/esp32h2"]
-esp32s2 = ["esp-println?/esp32s2", "semihosting?/openocd-semihosting"]
-esp32s3 = ["esp-println?/esp32s3", "semihosting?/openocd-semihosting", "print-float-registers"]
+esp32   = ["esp-println?/esp32", "esp-metadata-generated/esp32", "semihosting?/openocd-semihosting", "print-float-registers"]
+esp32c2 = ["esp-println?/esp32c2", "esp-metadata-generated/esp32c2"]
+esp32c3 = ["esp-println?/esp32c3", "esp-metadata-generated/esp32c3"]
+esp32c6 = ["esp-println?/esp32c6", "esp-metadata-generated/esp32c6"]
+esp32h2 = ["esp-println?/esp32h2", "esp-metadata-generated/esp32h2"]
+esp32s2 = ["esp-println?/esp32s2", "esp-metadata-generated/esp32s2", "semihosting?/openocd-semihosting"]
+esp32s3 = ["esp-println?/esp32s3", "esp-metadata-generated/esp32s3", "semihosting?/openocd-semihosting", "print-float-registers"]
 
 ## Use `esp-println`
 println = ["dep:esp-println"]
@@ -60,6 +61,8 @@ custom-halt          = []
 custom-pre-backtrace = []
 ## Halt both CPUs on ESP32 / ESP32-S3 instead of doing a `loop {}` in case of a panic
 halt-cores           = []
+## Exit with a semihosting call in case of a panic
+semihosting = ["dep:semihosting"]
 ## Include a panic handler
 panic-handler        = []
 

esp-backtrace/build.rs

@@ -1,5 +1,16 @@
 use esp_config::generate_config_from_yaml_definition;
 
+#[macro_export]
+macro_rules! assert_unique_features {
+    ($($feature:literal),+ $(,)?) => {
+        assert!(
+            (0 $(+ cfg!(feature = $feature) as usize)+ ) <= 1,
+            "At most one of the following features must be enabled: {}",
+            [$($feature),+].join(", ")
+        );
+    };
+}
+
 #[macro_export]
 macro_rules! assert_unique_used_features {
     ($($feature:literal),+ $(,)?) => {
@@ -15,8 +26,17 @@ fn main() {
     // Ensure that exactly a backend is selected:
     assert_unique_used_features!("defmt", "println");
 
-    if cfg!(feature = "custom-halt") && cfg!(feature = "halt-cores") {
-        panic!("Only one of `custom-halt` and `halt-cores` can be enabled");
+    // Ensure that there aren't multiple halt methods selected:
+    assert_unique_features!("custom-halt", "halt-cores", "semihosting");
+
+    if !cfg!(feature = "panic-handler")
+        && cfg!(any(
+            feature = "custom-halt",
+            feature = "halt-cores",
+            feature = "semihosting"
+        ))
+    {
+        print_warning("A halt method is selected, but esp-backtrace is not the panic handler.")
     }
 
     // emit config
@@ -25,3 +45,7 @@ fn main() {
         .expect("Failed to read esp_config.yml for esp-backtrace");
     generate_config_from_yaml_definition(&cfg_yaml, true, true, None).unwrap();
 }
+
+fn print_warning(message: impl core::fmt::Display) {
+    println!("cargo:warning={message}");
+}

esp-backtrace/src/lib.rs

@@ -25,6 +25,9 @@
 #![doc(html_logo_url = "https://avatars.githubusercontent.com/u/46717278")]
 #![no_std]
 
+#[macro_use]
+extern crate esp_metadata_generated;
+
 #[cfg(feature = "defmt")]
 use defmt as _;
 #[cfg(feature = "println")]
@@ -120,67 +123,17 @@ fn panic_handler(info: &core::panic::PanicInfo) -> ! {
     abort();
 }
 
-// Ensure that the address is in DRAM and that it is 16-byte aligned.
+// Ensure that the address is in DRAM.
 //
-// Based loosely on the `esp_stack_ptr_in_dram` function from
-// `components/esp_hw_support/include/esp_memory_utils.h` in ESP-IDF.
-//
-// Address ranges can be found in `components/soc/$CHIP/include/soc/soc.h` as
-// `SOC_DRAM_LOW` and `SOC_DRAM_HIGH`.
+// Address ranges can be found in `esp-metadata/devices/$CHIP.toml` in the `device` table.
 fn is_valid_ram_address(address: u32) -> bool {
-    if (address & 0xF) != 0 {
-        return false;
-    }
-
-    #[cfg(feature = "esp32")]
-    if !(0x3FFA_E000..=0x4000_0000).contains(&address) {
-        return false;
-    }
-
-    #[cfg(feature = "esp32c2")]
-    if !(0x3FCA_0000..=0x3FCE_0000).contains(&address) {
-        return false;
-    }
-
-    #[cfg(feature = "esp32c3")]
-    if !(0x3FC8_0000..=0x3FCE_0000).contains(&address) {
-        return false;
-    }
-
-    #[cfg(feature = "esp32c6")]
-    if !(0x4080_0000..=0x4088_0000).contains(&address) {
-        return false;
-    }
-
-    #[cfg(feature = "esp32h2")]
-    if !(0x4080_0000..=0x4085_0000).contains(&address) {
-        return false;
-    }
-
-    #[cfg(feature = "esp32s2")]
-    if !(0x3FFB_0000..=0x4000_0000).contains(&address) {
-        return false;
-    }
-
-    #[cfg(feature = "esp32s3")]
-    if !(0x3FC8_8000..=0x3FD0_0000).contains(&address) {
-        return false;
-    }
-
-    true
+    memory_range!("DRAM").contains(&address)
 }
 
 #[cfg(feature = "halt-cores")]
-fn halt() -> ! {
-    cfg_if::cfg_if! {
-        if #[cfg(feature = "custom-halt")] {
-            // call custom code
-            unsafe extern "Rust" {
-                fn custom_halt() -> !;
-            }
-            unsafe { custom_halt() }
-        } else if #[cfg(any(feature = "esp32", feature = "esp32s3"))] {
-            // multi-core
+fn halt() {
+    #[cfg(any(feature = "esp32", feature = "esp32s3"))]
+    {
         #[cfg(feature = "esp32")]
         mod registers {
             pub(crate) const OPTIONS0: u32 = 0x3ff48000;
@@ -212,9 +165,6 @@ fn halt() -> ! {
             );
         }
     }
-    }
-
-    loop {}
 }
 
 #[cfg(feature = "panic-handler")]
@@ -236,13 +186,20 @@ fn abort() -> ! {
 
     cfg_if::cfg_if! {
         if #[cfg(feature = "semihosting")] {
+            critical_section::with(|_| {
                 semihosting::process::abort();
+            });
         } else if #[cfg(feature = "halt-cores")] {
             halt();
-        } else {
-            critical_section::with(|_| {
-                loop {}
-            })
+        } else if #[cfg(feature = "custom-halt")] {
+            // call custom code
+            unsafe extern "Rust" {
+                fn custom_halt() -> !;
+            }
+            unsafe { custom_halt() }
         }
     }
+
+    #[allow(unreachable_code)]
+    critical_section::with(|_| loop {})
 }